U.S. patent application number 12/509981 was filed with the patent office on 2010-02-04 for process for producing resin molded article.
This patent application is currently assigned to HITACHI MAXELL, LTD.. Invention is credited to Tetsuya ANO, Toshiyuki OGANO, Satoshi YAMAMOTO, Atsushi YUSA.
Application Number | 20100025880 12/509981 |
Document ID | / |
Family ID | 41607502 |
Filed Date | 2010-02-04 |
United States Patent
Application |
20100025880 |
Kind Code |
A1 |
ANO; Tetsuya ; et
al. |
February 4, 2010 |
PROCESS FOR PRODUCING RESIN MOLDED ARTICLE
Abstract
There is disclosed a process for producing a resin molded
article by using a resin into which fine metal particles are so
introduced as to be hardly dissolved at the melting temperature of
the resin and as to obtain high solubility in a high-pressure
carbon dioxide. This process comprises the steps of forming a
high-pressure fluid by dissolving, in a high-pressure carbon
dioxide, a fluorine-containing metal complex and a fluorine-based
solution capable of dissolving the same metal complex; introducing
the high-pressure fluid into a heated and molten resin; and molding
the resin having the high-pressure fluid introduced thereinto, to
shape the molded article.
Inventors: |
ANO; Tetsuya; (Osaka,
JP) ; YUSA; Atsushi; (Osaka, JP) ; YAMAMOTO;
Satoshi; (Osaka, JP) ; OGANO; Toshiyuki;
(Kasukabe-shi, JP) |
Correspondence
Address: |
BIRCH STEWART KOLASCH & BIRCH
PO BOX 747
FALLS CHURCH
VA
22040-0747
US
|
Assignee: |
HITACHI MAXELL, LTD.
Ibaraki-shi
JP
|
Family ID: |
41607502 |
Appl. No.: |
12/509981 |
Filed: |
July 27, 2009 |
Current U.S.
Class: |
264/129 ;
264/328.1 |
Current CPC
Class: |
C08J 5/10 20130101; B29C
45/1706 20130101; C08J 2377/02 20130101 |
Class at
Publication: |
264/129 ;
264/328.1 |
International
Class: |
B05D 1/18 20060101
B05D001/18; B29C 45/18 20060101 B29C045/18 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 28, 2008 |
JP |
2008-193557 |
Claims
1. A process for producing a resin molded article, comprising the
steps of forming a high-pressure fluid by dissolving, in a
high-pressure carbon dioxide, a fluorine-containing metal complex
and a fluorine-based solution capable of dissolving said metal
complex, introducing said high-pressure fluid into a heated and
molten resin, and molding the resin into which said high-pressure
fluid has been introduced, to shape the resin molded article.
2. The process of claim 1, wherein the dissolution of said
fluorine-containing metal complex and said fluorine-based solution
in said high-pressure carbon dioxide comprises the steps of
dissolving said fluorine-containing metal complex in said
fluorine-based solution, and dissolving, in said high-pressure
carbon dioxide, said fluorine-based solution in which said
fluorine-containing metal complex is dissolved.
3. The process of claim 2, wherein the dissolution of said
fluorine-containing metal complex in said fluorine-based solution
comprises the steps of dissolving said fluorine-containing metal
complex in said fluorine-based solution to form a mixture solution,
and allowing said mixture solution to have a high pressure.
4. The process of claim 1, wherein the dissolution of said
fluorine-containing metal complex and said fluorine-based solution
in said high-pressure carbon dioxide comprises the steps of
dissolving and saturating said fluorine-containing metal complex
and said fluorine-based solution in a first high-pressure carbon
dioxide, and mixing said first high-pressure carbon dioxide in
which said fluorine-containing metal complex and said
fluorine-based solution are dissolved and saturated, with a second
high-pressure carbon dioxide in which any of said
fluorine-containing metal complex and said fluorine-based solution
is not dissolved.
5. The process of claim 1, using an injection-molding apparatus
comprising a mold and a heating cylinder which heats and melts said
resin and injects the heated and molten resin into said mold,
wherein the introduction of said high-pressure fluid into said
heated and molten resin comprises the step of introducing said
high-pressure fluid into said resin which is heated and molten in
said heating cylinder; and the molding of said resin into which
said high-pressure fluid is introduced comprises the step of
injecting said resin into which said high-pressure fluid is
introduced, into said mold from said heating cylinder.
6. The process of claim 1, further comprising a step of subjecting,
to a heat treatment, said molded article shaped of said resin into
which said high-pressure fluid is introduced.
7. The process of claim 1, further comprising a step of subjecting,
to a vacuuming treatment, said molded article shaped of said resin
into which said high-pressure fluid is introduced.
8. The process of claim 1, wherein said fluorine-based solution has
a boiling point of from 150 to 400.degree. C.
9. The process of claim 1, wherein the molecular weight of said
fluorine-based solution is from 500 to 15,000.
10. The process of claim 1, wherein a high-pressure carbon dioxide
having a pressure of from 5 to 25 MPa is used as said high-pressure
carbon dioxide in which said fluorine-containing metal complex and
said fluorine-based solution are dissolved.
11. The process of claim 1, wherein said metal complex is
hexafluoroacetylacetonatopalladium (II) or nickel (II)
hexafluoroacetylacetonatohydride, and wherein said fluorine-based
solution is perfluorotripentylamine or
perfluoro-2,5,8,11,14-pentamethyl-3,6,9,12,15-pentaoxaoctadecanoyl
fluoride.
12. The process of claim 1, further comprising a step of forming a
metal film on said molded article.
13. The process of claim 12, wherein the formation of said metal
film on said molded article comprises a step of bringing said
molded article into contact with a fluid in which another
high-pressure carbon dioxide is compatiblized with a plating
solution.
Description
TECHNICAL FIELD
[0001] The present application is filed, claiming the Paris
Convention priorities of Japanese Patent Application No.
2008-193557 (filed on Jul. 28, 2008), the entire content of which
is incorporated herein by reference.
[0002] The present invention relates to a process for producing a
resin molded article.
BACKGROUND ART
[0003] Recently, the use of supercritical fluids such as
supercritical carbon dioxide, etc. as solvents has been vigorously
studied. While supercritical fluids have a surface tension of zero
and thus can be as well diffused as gases, such fluids can be used
as solvents because of their densities close to those of liquids.
As one of the novel production processes by making effective use of
the physical properties of such supercritical fluids, there is
proposed nonelectrolytic plating of plastic molded articles (cf.
Non-Patent Publication 1). Nonelectrolytic plating with use of a
supercritical fluid makes it possible to overcome the following
problems of the conventional technology of the nonelectrolytic
plating of plastic molded articles.
[0004] The conventional nonelectrolytic plating is widely employed
as means for forming metal films on resin molded articles for
electronic equipment, etc. In general, a conventional
nonelectrolytic plating process comprises the steps of molding a
resin, degreasing the resin molded article, etching the molded
article, neutralizing and wetting the etched molded article, adding
a catalyst, activating the catalyst, and subjecting the molded
article to nonelectrolytic plating, while there may be some
difference in the steps, depending on materials to be used.
[0005] In the etching step, a chromic acid solution, an alkali
metal hydroxide solution or the like is used.
[0006] Therefore, a post-treatment such as neutralization of an
etchant is needed in the conventional nonelectrolytic plating, and
such a post-treatment becomes one of factors of high cost. The use
of a highly toxic etchant in the etching step induces problems in
handling of the etchant. In the Europe, there was constituted the
regulation of RoHS (RoHS: Restriction of the use of certain
Hazardous Substances in electrical and electronic equipment). Under
this regulation, the manufactures of the materials and the electric
and electronic components have been obligated to guarantee that
electric and electronic equipment newly put on the European market
after Jul. 1, 2006 should contain no chromium (VI) or the like. It
is also an urgent mission for the manufactures to change the
conventional nonelectrolytic plating of plastics which heavily
burdens the environment, over to an alternative nonelectrolytic
plating process.
[0007] According to the process disclosed in Non-Patent Publication
1, an organic metal complex is dissolved in supercritical carbon
dioxide, and a variety of polymer molded articles are brought into
contact with this supercritical carbon dioxide. By doing so, the
organic metal complex is infiltrated in the surfaces of the polymer
molded articles. The polymer molded articles infiltrated by the
organic metal complex are further treated by heating or chemical
reduction, so that the organic metal complex is reduced to deposit
fine metal particles. A sequence of treatments as described above
modify the surfaces of the polymer molded articles so as to enable
nonelectrolytic plating on the polymer molded articles. Since this
process comprises no etching step, any treatment of the waste of
the etchant is not needed, differently from the conventional
nonelectrolytic plating. It is also not needed to roughen the
surfaces of the molded articles with the etchant so as to ensure
tight adhesion of the plated films to the molded articles.
Therefore, the surfaces of the molded articles and the plated films
are superior in smoothness to those obtained by the conventional
nonelectrolytic plating with the use of an echant.
[0008] However, the nonelectrolytic plating with the use of the
supercritical fluid, disclosed in Non-Patent Publication 1, has the
following problem: the polymer molded article is softened at its
surface by the supercritical carbon dioxide after the molding step,
to thereby infiltrate the supercritcal fluid and the metal complex
as a modifier in the polymer molded article. Consequently, the
contour of the molded article deforms due to such softening, and
thus, molding precision of the molded article can not be
maintained. The nonelectrolytic plating with the use of the
supercritical fluid, according to Non-Patent Publication 1, is poor
in continuous productivity, because this plating is a batch process
in which polymer molded articles are set in a high-pressure
container so that the metal complex is infiltrated in the polymer
molded articles. This plating is also unsuitable for plating of
large-size molded articles, since a high-pressure container
corresponding to such large size is needed.
[0009] The present inventors have proposed a method for modifying
the surface of a molded article so as to enable nonelectrolytic
plating on the molded article by applying this process principle to
segregate fine metal particles on a plastic molded article in
injection molding (Patent Publication 1), This is described in
detail: for example, fine metal particles of a metal complex or the
like are dissolved in a high-pressure supercritical carbon dioxide;
this solution of the supercritical carbon dioxide is charged in an
injection molding apparatus so as to introduce the supercritical
carbon dioxide into the flow front portion of the
thermoplasticizing cylinder of the injection molding apparatus; and
this thermoplastic resin is injection-molded, so that the fine
metal particles are segregated on the molded article simultaneously
with the injection molding. Thus, the fine metal particles which
act as catalytic nuclei for nonelectrolytic plating can infiltrate
the molded article concurrently with the molding, and additionally,
the fine metal particles can be segregated on the surface portion
of the molded article. Moreover, pre-treatments for plating such as
the above-described steps for infiltration and etching are not
required between the molding step and the plating step. [0010]
Non-Patent Publication 1: "Latest Applied Technology of
Supercritical Fluid" by Teruo Hori, issued by NTS Co., Ltd., pp.
250 to 255, 2004 [0011] Patent Publication 1: JP-B2-2625576
PROBLEM TO BE SOLVED BY THE INVENTION
[0012] However, as a result of the present inventors' studies, it
is found that, in the surface-modifying method for a molded article
described in Patent Publication 1, it is needed to select such fine
metal particles that can withstand the melting temperature of the
resin, as the fine metal particles to be introduced into the resin.
That is, once a resin to be used for a molded article is
determined, the kind of usable fine metal particles is limited
depending on the melting temperature of the resin.
[0013] Again, according to the surface-modifying method of Patent
Publication 1, a high-pressure carbon dioxide is used to introduce
the fine metal particles into the resin. It is therefore found to
be needed to select such fine metal particles that can be
sufficiently dissolved in the high-pressure carbon dioxide. It is
also found that the maximal amount of the fine metal particles
introduced into the resin is double restricted by the solubility of
the fine metal particles in the supercritical carbon dioxide and
the maximal amount of the supercritical carbon dioxide introduced
into the resin.
[0014] In the surface-modifying method of Patent Publication 1, as
the fine metal particles (i.e., the metal material as the catalytic
nuclei for plating), it is desirable to select such fine metal
particles that can be sufficiently dissolved in a high-pressure
supercritical carbon dioxide and are hardly modified or
precipitated before they are sufficiently diffused immediately
after introduced into a heated and molten thermoplastic resin. In
other words, desirable as the fine metal particles are those which
are hardly decomposed by heat even under a high temperature
atmosphere in a molding apparatus and have an extremely high
solubility in a high-pressure carbon dioxide. However, fine metal
particles which can concurrently satisfy these two requirements are
rare.
[0015] Under such a situation, the present inventors have
intensively studied in another approach without paying attentions
to the fine metal particles. As a result, it is found that the use
of a metal complex in a predetermined state is effective to
increase the solubility of the metal complex in a high-pressure
carbon dioxide, and that the metal complex itself is hard to be
thermally decomposed at a temperature higher than its thermally
decomposing temperature. The present invention is accomplished
based on such findings.
[0016] An object of the present invention is to provide a process
for producing a resin molded article, comprising the steps of
introducing fine metal particles into a resin so that the fine
metal particles can become hard to be thermally decomposed at a
melting temperature of the resin and also can have high solubility
in a high-pressure carbon dioxide; and molding this resin to shape
the resin molded article.
MEANS FOR SOLVING THE PROBLEM
[0017] According to the first aspect of the present invention,
there is provided a process for producing a resin molded article,
the process comprising the steps of forming a high-pressure fluid
by dissolving a fluorine-containing metal complex and a
fluorine-based solution capable of dissolving the same metal
complex in a high-pressure carbon dioxide; introducing the
high-pressure fluid into a heated and molten resin; and molding the
resin having the high-pressure fluid introduced therein to shape a
molded article.
[0018] According to this first aspect, in the high-pressure fluid
introduced into the heated and molten resin, the
fluorine-containing metal complex and the fluorine-based solution
capable of dissolving the same metal complex are dissolved in the
high-pressure carbon dioxide. The fluorine-based solution is one of
fluorides and has a property to be easily dissolved in a
high-pressure carbon dioxide. For this reason, the dissolution of
the metal complex in the high-pressure carbon dioxide is
facilitated, even if the metal complex itself has no property to be
easily dissolved in a high-pressure carbon dioxide.
[0019] By mixing the fluorine-based solution into the high-pressure
fluid, the heat resistance of the metal complex is improved, so
that the metal complex becomes hard to be decomposed by heating.
This phenomenon is considered to be attributed to an event that the
metal complex is coated with the fluorine-based solution.
[0020] As described above, according to the first aspect, by
combining the fluorine-containing metal complex with the
fluorine-based solution, the heat resistance of the
fluorine-containing metal complex is improved, and the solubility
of the fluorine-containing metal complex in the high-pressure
carbon dioxide is increased. Therefore, it becomes possible to use
a metal complex which has never been used because of its thermally
decomposing temperature lower than the melting temperature of a
resin (i.e., a thermoplastic resin) or a metal complex which is not
sufficiently dissolved in a high-pressure carbon dioxide, for
surface modification of molded articles. In other words, it becomes
possible to broaden the selection range of metal complexes usable
for surface modification of molded articles, and it becomes
possible to include also metal complexes which have never been used
alone. Thus, the surfaces of molded articles can be modified by
using a metal complex selected from such a broadened range of metal
complexes, in other words, by using a metal complex which is hard
to be thermally decomposed even under a high temperature condition
and which can obtain high solubility in a high-pressure carbon
dioxide.
[0021] Further, according to the first aspect, a liquid but not a
solid is used as the fluoride, and therefore, the powdery metal
complex can be homogeneously mixed with the fluorine-based
solution. Thus, this effect produced by the mixing with the
fluorine-based solution (i.e., the fluoride) can be expected from
almost all of metal complexes to be dissolved in high-pressure
carbon dioxide.
[0022] Furthermore, according to the first aspect, the
fluorine-based solution contained in the high-pressure fluid
naturally volatilizes (or releases) from the molded article before
the resin having the high-pressure fluid introduced therein has
been completely molded, and thus, the fluorine-based solution is
not left to remain in the molded article. For this advantage, the
step of drawing the fluorine-based solution out of the molded
article is not needed. Thus, formation of a plated film without any
treatment for drawing the fluorine-based solution out of the molded
article becomes possible. In addition, the surface precision of the
molded article becomes equal to the precision of the mold. In this
regard, no remaining fluorine-based solution (or fluoride) present
in the molded article was confirmed by analyzing the molded
article. Moreover, the volatilization of the fluorine-based
solution facilitates the floating of the metal complex on the
surface of the molded article, so that the metal complex can easily
bleed out.
[0023] In the first aspect, the resin into which the high-pressure
fluid is introduced may be optionally selected from thermoplastic
resins and the like. Examples of such a resin include
polyester-based synthetic fibers, thermoplastic resins such as
polypropylene, polyethylene, polymethyl methlacrylate,
polycarbonate, amorphous polyolefin, polyetherimide, polyethylene
terephthalate, polyphenylene sulfite (PPS), ABS resin,
polyamidoimide, polylactic acid, polyphthalamide and nylon resin,
etc. Further, a composite material of some of them may be used.
Furthermore, there may be used a resin material comprising a knead
mixture of such a resin with any of inorganic fillers such as glass
fibers, carbon fibers, nano-carbon and minerals (e.g., calcium
carbonate).
[0024] As the high-pressure carbon dioxide, there may be used
supercritical carbon dioxide, subcritical carbon dioxide, liquid
carbon dioxide, gaseous carbon dioxide, etc. To improve the
solubility of the fluorine-based solution in the high-pressure
carbon dioxide, a small amount of an organic solvent such as
ethanol may be mixed as an entrainer into the high-pressure fluid.
As a medium which dissolves the fluorocompound to a certain degree,
there are exemplified an air, water, butane, pentane, methanol,
etc. other than the high-pressure carbon dioxide. Among those, the
high-pressure carbon dioxide is most preferable because of its
solubility in an organic material, comparable to n-hexane, its
non-polluting property and its high affinity to plastics.
[0025] A high-pressure carbon dioxide with a pressure of from 5 to
25 MPa is used as the high-pressure carbon dioxide capable of
dissolving the fluorine-containing metal complex and the
fluorine-based solution. The solubility of the metal complex or the
like in the high-pressure carbon dioxide tends to increase along
with an increase in the pressure. When the pressure is lower than 5
MPa, the solubility of the metal complex or the like becomes
extremely low, so that a surface-modifying effect (or the
infiltration effect of the fluorocompound) due to the metal complex
or the like can not be given to a molded plastic. When the pressure
exceeds 25 MPa, the infiltration effect of the fluorocompound
becomes too high, so that foaming of a molded plastic is likely to
be hard to inhibit.
[0026] The metal complex is used as the catalytic nuclei for
nonelectrolytic plating. While the metal complex may be optionally
selected, usable examples thereof include
hexafluoroacetylacetonatopalladium (II), nickel (II)
hexafluoroacetylacetonatohydride, copper (II)
hexafluoro-acetylacetonatohydrate,
hexafluoroacetylacetonatoplatinum (II),
hexafluoroacetylacetonato(trimethylphosphine)silver (I),
dimethyl(heptafluorooctanedionate)silver (AgFOD), etc. The use of a
fluorine-containing metal complex having a markedly high solubility
in a high-pressure carbon dioxide, for example,
hexafluoroacetylacetonatopalladium (II), is more preferable.
[0027] The fluorine-based solution is a solution of a
fluorocompound, which can be used as an aid to improve the
segregation of the metal complex on the surface of a molded
article. Examples of the fluorocompound include
perfluorotripentylamine,
perfluoro-2,5,8,11,14-pentamethyl-3,6,9,12,15-pentaoxaocdadecanoyl
fluoride, etc. For example, the solubility of fluorine-containing
hexafluoroacetylacetonatopalladium (II) in the high-pressure carbon
dioxide is very high and thus is very useful as the catalytic
nuclei for plating, but this metal complex is low in thermally
decomposing temperature, since the thermally decomposition-starting
temperature of this metal complex in an atmospheric air or a
nitrogen atmosphere is about 70.degree. C. Once dissolved in the
high-pressure carbon dioxide, the metal complex is slightly
improved in heat resistance and thus is not thermally decomposed
immediately after infiltrating a resin with a high temperature.
However, the metal complex is thermally decomposed when the
residence time in the resin becomes longer. Therefore, the metal
complex is thermally decomposed before it is homogeneously
dispersed in the resin. In this case, the fluorine-containing
hexafluoroacetylacetonatopalladium (II) is hard to be segregated
over the proximity of the surface of the molded article and may be
easily buried in the molded article due to its own weight. In the
meantime, the metal complex dissolved and saturated in the
high-pressure carbon dioxide becomes insoluble in the high-pressure
carbon dioxide due to an abrupt change in temperature or pressure,
so that the metal complex is likely to abnormally precipitate
before it is introduced into the resin. To suppress these
disadvantageous phenomena, it is effective to mix the
fluorine-based solution into the high-pressure fluid. Since the
metal complex is a fluorine-containing substance, the metal complex
becomes compatible with the fluorine-based solution of the same
type. In addition, the fluorine-based material is also sufficiently
dissolved in the high-pressure carbon dioxide, and thus acts to
improve the solubility of the metal complex.
[0028] The fluorine-based solution may have a boiling point of from
150 to 400.degree. C. The fluorine-based solution having a boiling
point of lower than 150.degree. C. immediately volatilizes upon
infiltrating the resin with a high temperature, and thus is hard to
be homogeneously dispersed in the resin. The present inventors'
studies also have revealed that the heat resistant temperature of
the metal complex, i.e., hexafluoroacetylacetonatopalldium (II), is
raised, when the metal complex having a low thermally decomposing
temperature is dissolved in the fluorine-based solution having a
high boiling point and is compatibilized therewith. This is
considered to come from the fact that the metal complex having
lower heat resistance is coated with the fluorine-based solution
having higher heat resistance so that the apparent heat resistant
temperature of the metal complex would be raised. However, the
fluorine-based solution having a boiling point higher than
400.degree. C., if used, excessively exerts the functions which
stably and thermally maintains the metal complex, and thus makes it
hard for the metal complex to function as a metal catalyst due to
the reduction thereof by heating, even if the metal complex is
infiltrated in the resin.
[0029] The molecular weight of the fluorine-based solution may be
from 500 to 15,000. The fluorine-based solution having a molecular
weight of more than 15,000 becomes hard to be drawn out of the
molten resin, and also becomes lower in solubility in the
high-pressure carbon dioxide. In addition, such a fluorine-based
solution becomes hard to bleed out to the surface portion of the
molded article during the injection molding, due to its heavy
molecular weight. As a result, the effect of homogeneously
dispersing the fluorocompound in the surface portion of the molded
article becomes lower. On the other hand, the fluorine-based
solution having a molecular weight of less than 500 becomes hard to
remain in the resin and thus is easily drawn out of the surface of
the resin when it is introduced into the resin. The molecular
weight of the fluorine-based solution is preferably within the
above-specified range, also in view of the compatibility thereof
with the resin.
[0030] Examples of the fluorocompound according to the first
aspect, which satisfies the solubility in the high-pressure carbon
dioxide, the molecular weight and the boiling point include a
solution of perfluorotripentylamine of the following formula 1 (the
molecular formula: C.sub.15F.sub.33N (molecular weight: 821.1;
boiling point: 220.degree. C., manufactured by Sinquest
Laboratory), and a solution of
perfluoro-2,5,8,11,14-pentamethyl-3,6,9,12,15-pentaoxaoctadecanoyl
fluoride of the following formula 2 (the molecular formula:
C.sub.18F.sub.36O.sub.6 (molecular weight: 996.2; boiling point:
235.degree. C., manufactured by Sinquest Laboratory):
##STR00001##
[0031] Examples of other fluorocompounds include
perfluoro-2,5,8-trimethyl-3,6,9-trioxadodecanoic acid methyl ester
(molecular weight: 676; boiling point: 196.degree. C.),
perfluorooctadecanoic acid (molecular weight: 915; boiling point:
235.degree. C.), perfluoro(tetradecahydrophenanthrene) (molecular
weight: 624; boiling point: 215.degree. C.), SpectraSynQ1621
(molecular weight: 2,120; boiling point: 220.degree. C.),
1H,1H-perfluoro-1-octadecanol (molecular weight: 900; boiling
point: 211.degree. C.),
Hecakis(1H,1H,5H-octafluoro-pentoxy)phosphazene (molecular weight:
1,521; boiling point: 207.degree. C.),
1,2-bis(dipentafluorophenyl-phosphino) ethane (molecular weight:
758; boiling point: 190.degree. C.), perfluorododecanoic acid
(molecular weight: 614; boiling point: 245.degree. C.),
perfluoro-2,5,8,11-tetramethyl-3,6,9,12-tetraoxapentadecanoyl
fluoride (molecular weight: 830; boiling point: 203.degree. C.),
perfluorohexadecanoic acid (molecular weight: 814; boiling point:
211.degree. C.), perfluoro-1,10-decanedicarboxylic acid (molecular
weight; 610; boiling point: 240.degree. C.), etc.
[0032] According to the first aspect of the present invention, the
dissolution of the fluorine-containing metal complex and the
fluorine-based solution in the high-pressure carbon dioxide may
include the steps of dissolving the fluorine-containing metal
complex in the fluorine-based solution, and dissolving the
fluorine-based solution having the fluorine-containing metal
complex dissolved therein, in the high-pressure carbon dioxide.
[0033] By firstly dissolving the fluorine-containing metal complex
in the fluorine-based solution to form a liquid mixture as
described above, the fluorine-containing metal complex can be
homogeneously mixed into the fluorine-based solution. When this
liquid mixture is dissolved in the high-pressure carbon dioxide
later, any fluorine-containing metal complex that is not protected
by the fluorine-based solution is not allowed to be present in the
liquid mixture. Thus, the heat resistance of substantially all of
the metal complex can be improved.
[0034] Again, according to the first aspect of the present
invention, the dissolution of the fluorine-containing metal complex
in the fluorine-based solution further may include the steps of
forming the liquid mixture by dissolving the fluorine-containing
metal complex in the fluorine-based solution, and allowing the
liquid mixture to have a higher pressure.
[0035] As described above, the fluorine-containing metal complex is
firstly dissolved in the fluorine-based solution, and then, the
resulting liquid mixture is allowed to have a high pressure. By
doing so, the treatment to dissolve the fluorine-containing metal
complex in the fluorine-based solution can be carried out under a
low pressure environment (i.e., under a normal pressure
environment). Therefore, the fluorine-containing metal complex can
be dissolved in the fluorine-based solution in a container opened
to an atmospheric air. In contrast, for example, when no
fluorine-based solution is used, the fluorine-containing metal
complex is charged in a high-pressure container and is then mixed
with a high-pressure carbon dioxide in this high-pressure
container. Therefore, in order to maintain the dissolved
concentration (or solubility) of the metal complex, it is needed to
decompress the high-pressure container, to open or close the same
container and compress the same container so as to periodically add
the metal complex. This operation of charging the metal complex is
one of the factors to decrease the continuous productivity.
However, by dissolving the fluorine-containing metal complex in the
fluorine-based solution in the above-described container opened to
an atmospheric air, the continuous productivity is not decreased by
the operation of charging the metal complex.
[0036] Again, according to the first aspect, the dissolution of the
fluorine-containing metal complex and the fluorine-based solution
in the high-pressure carbon dioxide may include the steps of
dissolving and saturating the fluorine-containing metal complex and
the fluorine-based solution in a first high-pressure carbon
dioxide; and mixing the first high-pressure carbon dioxide having
the fluorine-containing metal complex and the fluorine-based
solution dissolved and saturated therein, with a second
high-pressure carbon dioxide having no fluorine-containing metal
complex and no fluorine-based solution dissolved therein.
[0037] By the dissolution and saturation of the metal complex and
the fluorine-based solution in the first high-pressure carbon
dioxide, followed by the mixing with the second high-pressure
carbon dioxide, the metal complex and the fluorine-based solution
can have unsaturation solubility in the high-pressure fluid
obtained after the mixing. In case where the metal complex and the
fluorine-based solution are dissolved with saturation solubility,
the thermal decomposition or the abnormal precipitation of the
metal complex is apt to occur because of an abrupt change in
temperature or pressure, caused when the metal complex is
introduced, for example, into the heating cylinder in the course of
supplying the metal complex to the molding apparatus. However, such
a problem is not caused in the present invention.
[0038] In addition, the mixing ratio of the second high-pressure
carbon dioxide to the first high-pressure carbon dioxide is
adjusted to thereby reliably control the solubility of the metal
complex or the like in the high-pressure fluid obtained after the
mixing, to a desired unsaturation solubility. Since the solubility
of the metal complex or the like can be stabilized at a desired
unsaturation solubility, the amount of the metal complex to be
introduced into the resin can be readily and optimally controlled
by controlling the supply time of this high-pressure fluid or the
like.
[0039] In contrast, in case where only an expensive material such
as the metal complex is dissolved in a high-pressure carbon
dioxide, the metal complex is dissolved in the high-pressure carbon
dioxide with saturation solubility, so as to stabilize the amount
of the metal complex dissolved in the high-pressure carbon dioxide
(or to stabilize the amount of the metal complex introduced into
the resin). In this case, the thermal decomposition or abnormal
precipitation of the metal complex is apt to occur because of the
dissolution and saturation of the metal complex, which results in
higher cost.
[0040] That is, in case where the metal complex is dissolved in the
high-pressure carbon dioxide with the saturation solubility, it is
needed to control the amount of the metal complex supplied to the
resin by the amount of carbon dioxide supplied to the resin.
However, it is not sufficient to simply supply the high-pressure
carbon dioxide to the resin, but it is needed to supply the
high-pressure carbon dioxide in an optimal amount in accordance
with the volume of a molded article and molding conditions. This is
because too small an amount of the high-pressure carbon dioxide
supplied to the resin makes it difficult to sufficiently diffuse
the metal complex in the resin. On the other hand, too large an
amount of the high-pressure carbon dioxide supplied to the resin
becomes impossible to infiltrate the resin, so that the metal
complex is apt to separate. When the metal complex or the like can
not completely infiltrate the resin, the resultant molded article
tends to deform, or foaming tends to occur in the molded article.
Since the amount of the high-pressure carbon dioxide supplied to
the resin is needed to be optimized, the amount of the metal
complex supplied to the resin is determined depending on the amount
of the high-pressure carbon dioxide supplied to the resin, even
when the amount of the metal complex supplied to the resin is
controlled by the amount of the high-pressure carbon dioxide
supplied to the resin. As a result, the metal complex dissolved in
the high-pressure carbon dioxide with the saturation solubility is,
in principle, excessively supplied to the resin. In contrast,
according to the first aspect of the present invention, the amount
of the high-pressure carbon dioxide supplied to the resin and the
amount of the metal complex supplied to the resin can be
independently and separately controlled, so that these two supply
amounts can be optimized. Consequently, the thermal decomposition
or the abnormal precipitation of the metal complex can be
prevented, while an optimal amount of the high-pressure carbon
dioxide being supplied to the resin, and further, the excessive
supply of the metal complex is prevented to thereby suppress
cost-up.
[0041] In the first aspect of the present invention, the
resin-molding method may be optionally selected: injection molding,
extrusion molding or compression molding is preferable. In case of
injection molding, the high-pressure fluid may be introduced into
the plasticized molten resin in the flow front portion as the
leading end of the heating cylinder, during a suck-back operation
after a weighing operation (the flow front method); or a clearance
is formed between the filled resin and the mold by moving the mold
charged with the injected resin, and the high-pressure fluid is
introduced into this clearance (the core back method); or the
plasticized molten resin and the high-pressure fluid in one of two
heating cylidners are entirely kneaded, and this knead mixture is
divided into the two heating cylinders for sandwich molding or
two-color molding, to thereby modify only the surface skin or a
part of the resultant molded article by the use of the
high-pressure carbon dioxide, and such a modified material is used
for molding (the screw kneading method).
[0042] Again, according to the first aspect of the present
invention, there is provided a process for producing a resin molded
article, using an injection-molding apparatus which comprises a
mold and a heating cylinder which heats and melts a resin and
injects the molten resin into the mold, wherein the introduction of
a high-pressure fluid into the heated and molten resin may include
the step of introducing the high-pressure fluid into the resin
heated and molten in the heating cylinder; and the molding of the
resin having the high-pressure fluid introduced thereinto may
include the step of injecting the resin having the high-pressure
fluid introduced thereinto, from the heating cylinder into the
mold. In this case, the resin which has the high-pressure fluid
introduced thereinto and is then kneaded may be the resin in a
whole of the heating cylinder or the resin only in the flow front
portion in the front of the screw.
[0043] By introducing the high-pressure fluid into the heating
cylinder of the injection molding apparatus, the metal complex or
the like can be directly introduced into the molten resin.
Therefore, a desired surface-modifying effect can be produced for a
molded article, using the necessary and smallest amount of the
metal complex, in comparison with the case where a molded article
is placed together with the metal complex in a high-pressure
container so that the metal complex is infiltrated in the molded
article. Thus, the amount of the metal complex to be used for every
one operation can be reduced without impairing the
surface-modifying effect by the metal complex. The high-pressure
fluid contains the fluorine-based solution, and thus, the heat
resistance of the metal complex is improved, so that the metal
complex is not thermally decomposed or precipitated at the
introduction inlet of the cylinder heated to a high temperature so
as to melt the resin, immediately after the introduction of the
metal complex. Therefore, the metal complex can be almost
homogeneously mixed into the molten resin in the heating
cylinder.
[0044] In this process for producing the resin molded article with
the use of the injection molding apparatus, the high-pressure
carbon oxide having the fluorine-based solution (or the
fluorocompound) dissolved therein is introduced, for example, into
the flow front portion of the molten resin in the heating cylinder.
After that, the molten resin in the same cylinder is injected into
the mold, and then, firstly, the flow front portion of the molten
resin, having the fluorine-based solution infiltrated therein, is
injected into the mold, and then, the molten resin in which the
fluorine-based solution is not infiltrated is injected into the
mold.
[0045] When the flow front portion of the molten resin, having the
fluorine-based solution infiltrated therein, is injected into the
mold, the same molten resin is pulled to the inner surface of the
mold to be in contact therewith due to a fountain flow phenomenon
(a fountain effect) of the flowing resin within the mold, and the
molten resin is diffused within the mold while being in contact
with the inner surface of the mold as above. When the molten resin
having no fluorine-based solution infiltrated therein is then
injected into the mold, the molten resin spreads entering the inner
portion of the flow front portion of the molten resin which already
has been injected into the mold, to thereby push and spread the
mass of the flow front portion of the molten resin from the inner
side. Why this fountain flow phenomenon occurs is, for example,
that the resin is hard to flow due to contact resistance between
the resin and the inner surface of the mold at a portion where the
resin contacts, while the center and inner portion of the resin is
considered to be easy to flow.
[0046] Thus, the surface portion (i.e., the surface layer or the
skin layer) of the molded article is formed of the flow front
portion of the molten resin. That is, in this process for producing
the resin molded article, there can be obtained the molded article
which comprises the skin layer having the fluorine-based solution
(or the fluorocompound) dispersed therein, and the core layer
having substantially no fluorine-based solution (or the
fluorocompound) dispersed therein. That is, the metal complex can
be effectively segregated over the surface portion (or the skin
layer) of the molded article, while unnecessary distribution of the
metal complex in the inner portion (or the core layer) of the
molded article is being prevented.
[0047] The fluorine-based solution (or the fluorocompound) in the
skin layer is lower in surface energy because of the content of
fluorine and has a lower molecular weight, and thus moves to float
to the surface of the skin layer (or bleeds out). The
fluorine-containing metal complex or a modified product thereof
also tends to be maldistributed on the surface portion of the skin
layer. In particular, it is considered that the metal complex,
compatibilized with the fluorine-based solution, is more likely to
bleed out, as compared with the metal complex alone. As a result,
the fluorine-based solution (or the fluorocompound) and the metal
complex or the modified product thereof are maldistributed on the
surface portion of the skin layer, before the molding of the resin
within the mold has been completed.
[0048] For this advantage, in the process for producing the resin
molded article with the use of the injection molding apparatus, the
fluorine-based solution (or the fluorocompound) having a certain
solubility in the high-pressure carbon dioxide, the metal complex
dissolved together with this solution, etc. can be infiltrated at a
high concentration in the surface portion of any of a variety of
molded articles. This resin molded article-producing process with
the use of the injection molding apparatus can be applied to the
surface-modifying techniques for a variety of molded articles. That
is, the surface-modifying step for the molded article can be
carried out concurrently with the molding step. Further, the
fluorine contained in the fluorine-based solution bleeds out to the
surface of the molded article to thereby effectively function as a
mold releasing agent, so that the releasability of the mold is also
improved.
[0049] Again, according to the first aspect of the present
invention, the process may include a step for conducting a heat
treatment or a vacuuming treatment on the molded article shaped of
the resin having the high-pressure fluid introduced therein.
[0050] By the heat treatment or the vacuuming treatment of the
molded article, the metal complex or the modified product thereof
residual in the molded article is bled out to the surface of the
molded article (as if being pushed up to move to the surface of the
molded article). As a result, the concentration of the metal
complex or the modified product thereof in the surface portion with
a depth of several microns from the surface of the molded article
can be further increased. As a result, a sufficient amount of the
metal complex or the like can be reliably ensured in the surface
portion with a depth of several microns from the surface of a whole
of the molded article, and an uniform and high strength can be
obtained as the adhesion strength of a plated film which is grown
using the metal complex as catalytic nuclei. Further, the amount of
expensive materials such as the metal complex to be used can be
reduced by suppressing the addition amount of the metal complex to
the minimum. In case where the metal complex is used as the
catalytic nuclei for plating, the amount of the metal complex to be
used for one operation of molding can be decreased without any
decrease of the amount of the metal complex to be effectively used
for plating.
[0051] It becomes possible to collect the metal complex or the like
in the proximity of the surface of the resin molded article by the
above-described injection molding wherein the high-pressure fluid
is introduced into the flow front portion of the molten resin.
However, it is difficult to control the concentration distribution
of the metal complex or the like in the depth direction in the
order of submicron. In addition, the concentration distribution of
the metal complex is apt to change, depending on subtle differences
in molding conditions and the shapes of molded articles, even when
the molded articles are shaped using the same apparatus. To
overcome this problem, the present inventors have studied and
considered that it is the most effective to infiltrate the metal
complex in the surface of the molded article to a depth in the
order of submicron from the surface thereof, so as to cause the
metal complex or the like to function as catalytic nuclei for
plating. Then, a heat treatment or a vacuuming treatment is
conducted on the resultant molded article, so that the
concentration of the metal complex or the like in the surface
portion with a depth in the order of submicron from the uppermost
surface of the molded article can be stabilized at a high level to
thereby suppress a variation of the concentration. As a result, the
variation in the adhesion of the plated film can be suppressed.
[0052] As described above, the fluorine-based solution introduced
together with the metal complex into the heating cylinder already
has been drawn out from the molded article before the completion of
the molding. Therefore, the fluorine-based solution or the metal
complex does not bleed out from the molded article, even when a
heat treatment or a vacuuming treatment is made on the molded
article. Thus, formation of holes (numerous pores in the order of
nanometer) due to such bleeding can be prevented. Therefore, the
surface roughness of the molded article is not accelerated, even
when a heat treatment or a vacuuming treatment is made on the
molded article. That is, the concentration of the metal complex or
the like in the surface portion of the molded article can be
increased without impairing the smoothness of the molded
article.
[0053] Again, according to the first aspect of the present
invention, the process further may include a step of forming a
metal film on the molded article.
[0054] The metal complex or the modified product thereof is
infiltrated in the surface portion of the molded article shaped by
the process according to the first aspect. Therefore, a plated film
can be formed by using this metal complex or the modified product
thereof as catalytic nuclei for the growth of the plated film. As a
result, the plating treatment can be made on the molded article
without any pre-treatment, and thus, the plated film with a high
adhesion strength can be formed.
[0055] In particular, by conducting the bleed-out treatment on the
resultant molded article, the density of the metal complex or the
like in the surface portion of the molded article can be increased.
In addition, the surface of the primer layer of the molded article
is not roughened as in the conventional nonelectolytic plating
process including an etching step, and thus, a plated film with a
high surface smoothness can be formed with an adhesion strength
equal or superior to that of a plated film formed by the
conventional nonelectrolytic plating process.
[0056] The formation of the metal film on the molded article may
include a step of bringing the molded article into further contact
with a fluid in which other high-pressure carbon dioxide and a
plating solution are compatible with each other. In this regard, a
stirring means such as a magnetic stirrer may be used to
compatibilize the high-pressure carbon dioxide with the plating
solution.
[0057] By compatibilizing the high-pressure carbon dioxide with the
plating solution, it becomes possible for the plating solution to
deeply infiltrate the molded article with a higher infiltration
force, together with the high-pressure carbon dioxide.
Consequently, the plated film deeply grows to have an adhesion
strength equal or superior to that of a plated film formed by the
conventional nonelectrolytic plating process including an etching
step, while the molded article is maintaining a smooth surface.
EFFECT OF THE INVENTION
[0058] As described above, according to the process for producing a
resin molded article of the present invention, fine metal particles
so treated as to be hard to be thermally decomposed at a melting
temperature of a resin and as to have high solubility in a
high-pressure carbon dioxide are introduced into the resin, and
such a resin is molded to modify the surface of a molded
article.
BEST MODES FOR CARRYING OUT THE INVENTION
[0059] Hereinafter, examples of the process for producing a resin
molded article, according to the present invention, will be
described with reference to the accompanying drawings. However, the
following examples are preferred examples of the process of the
present invention, and thus, the scope of the present invention is
not limited to the details thereof in any way.
BRIEF DESCRIPTION OF DRAWINGS
[0060] FIG. 1 shows the schematic diagram of the heat resistant
temperature-measuring apparatus used in the preliminary comparative
test.
[0061] FIG. 2 shows the table illustrating changes in the colors of
the fluids in the high-pressure containers shown in FIG. 1.
[0062] FIG. 3 shows the schematic diagram of the flow front
injection-molding apparatus used in Example 1, illustrating the
structure thereof.
[0063] FIG. 4, consisting of FIGS. 4(a) and 4(b), schematically
shows the states of the molten resin charged in the mold by
injecting, wherein FIG. 4(a) shows a state in which the charging of
the molten resin is started; and FIG. 4(b) shows a state in which
the charging of the molten resin is completed.
[0064] FIG. 5 shows the schematic diagram of the nonelectrolytic
plating apparatus used in Example 1, illustrating the structure
thereof.
[0065] FIG. 6 shows the schematic diagram of the flow front
injection-molding apparatus used in Example 3, illustrating the
structure thereof.
[0066] FIG. 7 shows the schematic diagram of the flow front
injection-molding apparatus used in Example 4, illustrating the
structure thereof
DESCRIPTION OF REFERENCE NUMERALS
[0067] 1 or 1'=a syringe pump [0068] 12 or 12'=a dissolution tank
[0069] 25=a material-stocking container [0070] 101=a mold [0071]
105=a plasticizing cylinder (or a heating cylinder) [0072] 1130=a
molded sample (or a molded body)
Preliminary Test Examples
[0073] Prior to the description of Examples, the preliminary test
examples conducted by the present inventors are described. The
preliminary test examples were made to compare the heat resistant
temperatures of metal complexes, affected by the presence or
absence of a fluorine-based solution. This is described in detail:
the heat resistant temperature of a metal complex was measured when
hexafluoroacetylacetonatopalladium (II) as the metal complex and
perfluorotripentylamine as a fluorine-based solution were dissolved
in a high-pressure carbon dioxide (hereinafter, this fluid being
referred to as a first fluid); and the heat resistant temperature
of the same metal complex was measured when the metal complex alone
was dissolved in a high-pressure carbon dioxide (hereinafter, this
fluid being referred to as a second fluid).
[0074] The heat resistant temperature-measuring apparatus used in
this comparative test is shown in FIG. 1. The heat resistant
temperature-measuring apparatus comprises a liquid carbon dioxide
bomb 2, a syringe pump 1, a high-pressure container 3 and a back
pressure valve 6 as main members. The high-pressure container 3
includes heaters 4, a sight window 9 and a stirrer b.
[0075] The inner volume of the high-pressure container 3 was 25 ml.
In the test for the first fluid, the metal complex (500 mg) and the
fluorine-based solution (10 g) were charged in this high-pressure
container 3. In the test for the second fluid, the same metal
complex (500 mg) alone was charged in this high-pressure
container.
[0076] A high-pressure carbon dioxide was supplied to the
high-pressure container 3 from the liquid carbon dioxide bomb 2
through the syringe pump 1. The inner pressure of the high-pressure
container 3 during the test was maintained by the back pressure
valve 6. The inlet valve 7 of the high-pressure container 3 was
closed, and then, the syringe pump 1 was used to supply the
high-pressure carbon dioxide with a pressure of 10 MPa at a normal
temperature to the high-pressure container 3. The temperature of
the high-pressure container 3 was raised by every 5.degree. C. per
one minute using the heater 4. The set pressure for the back
pressure valve 6 was 10 MPa. Therefore, the interior of the
high-pressure container 3 was always maintained at 10 MPs
independently of a change in the temperature.
[0077] FIG. 2 shows a table which indicates the changes of the
colors of the first fluid and the second fluid in the high-pressure
containers with the passage of time. The lower line of the table
shown in FIG. 2 is for the first fluid; and the upper line thereof,
for the second fluid. When the temperatures of the containers were
30.degree. C., respectively, both of the first fluid and the second
fluid were colored orange with the same optical density. This
orange color was attributed to hexafluoroacetylacetonato-palladium
(II).
[0078] Even when the temperatures of the containers were raised
from 30.degree. C., the colors of the first fluid and the second
fluid were not changed for a while and were maintained to be the
same colors with the same optical densities as those at 30.degree.
C.
[0079] When the second fluid indicated in the upper line was heated
to a temperature higher than the heat resistant temperature
(150.degree. C.) of hexafluoroacetylacetonatopalladium (II), the
orange color disappeared from the fluid. This was because the
orange-colored metal complex was decomposed by heat so that the
color of the fluid was changed from the orange color of the metal
complex to the transparent color of the high-pressure carbon
dioxide.
[0080] In contrast, the orange color of the first fluid in the
lower line was sustained, even when the fluid was heated to a
temperature higher than the heat resistant temperature (150.degree.
C.) of hexafluoroacetylacetonatopalladium (II). The orange color of
the first fluid was sustained even at 200.degree. C., and the first
fluid in the container did not turn transparent. This fact
indicates that the metal complex was not decomposed even when
heated to a temperature higher than the melting temperature.
Herein, perfluorotri-pentylamine was kept to be transparent within
the above-described temperature ranges.
[0081] From these test results for comparison, it is known that the
heat resistant temperature of the metal complex becomes higher by
dissolving the metal complex, i.e.,
hexafluoroacetylacetonatopalladium (II), in the high-pressure
carbon dioxide, together with perfluoro-tripentylamine. This is
considered as follows: hexafluoroacetylacetonatopalladium (II)
contains a fluorine atom, and perfluorotripentylamine has a
property to be easily compatible with a fluorine-containing metal
complex, so that, consequently, the fluorine-based solution
encloses the fluorine-containing metal complex in the high-pressure
container to protect the metal complex.
[0082] The melting temperature of a thermoplastic resin during
injection-molding or other molding thereof is generally 150.degree.
C. or higher. When the fluorine-containing metal complex having a
thermally decomposing temperature lower than the molding
temperature is dissolved in the fluorine-based solution, the metal
complex as it is can be supplied to the molten resin, accordingly.
In the meantime, the time while the metal complex is exposed to a
high temperature atmosphere during practical injection-molding is
several tens seconds. Accordingly, the apparent heat resistant
temperature of the metal complex dissolved in the fluorine-based
solution during the practical injection-molding is supposed to be
far higher than the heat resistant temperature measured in the
above-described test.
Example 1
[0083] In this Example, a high-pressure fluid which contained a
fluorine-containing metal complex, a fluorine-based solution and a
high-pressure carbon dioxide was infiltrated and dispersed in a
thermoplastic resin heated and molten in the heating cylinder of an
injection-molding apparatus; and the heated molten resin obtained
after the infiltration-and-dispersion treatment was molded to shape
a surface-modified molded article. The resultant molded article was
subjected to a heat treatment to bleed out the metal complex, and
then, a metal film was formed on the resulting molded article by
nonelectrolytic plating.
[0084] As the thermoplastic resin, there was used polyamide6
(Nylon6, Novamid GH10 manufactured by Mitsubishi
Engineering-Plastics Corporation) containing 10% of glass fibers.
As the fluorine-containing metal complex, there was used
hexafluoroacetylacetonatopalladium (II) of which the thermally
decomposing temperature was 150.degree. C. As the fluorine-based
solution which dissolved the metal complex, there was used
perfluorotripentylamine (the molecular formula: C.sub.15F.sub.33N
(manufactured by Sinquest Laboratory; molecular weight: 821.1; and
boiling point: 220.degree. C.). As the high-pressure carbon
dioxide, there was used a liquid carbon dioxide with a temperature
of 10.degree. C. and a pressure of 10 MPa.
Molding Apparatus
[0085] FIG. 3 shows the schematic diagram of a flow front
injection-molding apparatus used in this Example. This molding
apparatus 100 comprises an injection-molding section 100A and a
high-pressure carbon dioxide-generating section 100B. The
injection-molding section 100A includes a mold 101 which comprises
a movable mold 102 and a stationary mold 103. A disc-shaped cavity
106 having a spool at its center is formed when the movable mold
102 strikes the stationary mold 103. In this Example, the surfaces
of the movable mold 102 and the stationary mold 103 which defined
the cavity 106 are shaped as plane surfaces (mirror surfaces)
except for the portions corresponding to the center portion of the
cavity 106 (e.g., the spool, etc.).
[0086] The injection-molding section 100A includes a plasticizing
cylinder 105 which heats and melts a thermoplastic resin supplied
from a hopper (not shown) and injects the molten resin into the
cavity 106 of the mold 101. Further, a gas-introducing mechanism
107 is provided at the flow front portion 105A of the heating
cylinder 105 (or the plasticizing cylinder), and the high-pressure
carbon dioxide-generating section 100B is connected to this
gas-introducing mechanism 107. Other structure of the
injection-molding section 100A is similar to that of a conventional
injection-molding apparatus.
[0087] The high-pressure carbon dioxide-generating section 10B
comprises, as shown in FIG. 3, a carbon dioxide bomb 2, two known
syringe pumps (E-260, manufactured by ISCO) 1 and 1', a dissolution
tank 12, four air operation valves 10, 10', 11 and 11' which
interlock with the injection-molding section 100A to automatically
open or close, and two check valves 13 and 131.
[0088] The dissolution tank 12 was charged with a mixture solution
of hexafluoroacetylacetonatopalladium (II) as the metal complex and
perfluorotripentylamine as the fluorine-based solution (or a
fluorocompound). Specifically, the mixture solution of
perfluorotripentylamine in which hexafluoroacetylacetonatopalladium
(II) was completely dissolved was dispersed on a wet support, and
this wet support (manufactured by ISCO) as a liquid carrier was so
charged in the dissolution tank 12 as not to flow out when the
high-pressure carbon dioxide was supplied. These materials were
charged in sufficient amounts so as to always oversaturate.
Therefore, the mixture solution of the metal complex and the
fluorocompound was always saturation-dissolved in the high-pressure
carbon dioxide in the dissolution tank 12. The operation of
charging these materials was carried out, for example, by closing
two manual valves 18 and 19, and releasing a pressure from the
dissolution tank 12 with a manual valve (not shown) to void the
dissolution tank 12 for charging the wet support.
[0089] The high-pressure carbon dioxide in the carbon dioxide bomb
2 was firstly supplied to the syringe pumps 1 and 11 through a
manual valve 16, a filter 17 and the air operation valves 10 and
10' on the suction side, respectively. In this operation, the
manual valve 16 and the air operation valves 10 and 10' on the
suction side were opened, and the air operation valves 11 and 11'
on the supply side were closed. Pistons (not shown) in the
respective syringe pumps 1 and 1' were caused to move backward so
that the liquid carbon dioxide cooled to 10.degree. C. was sucked
into the respective syringe pumps 1 and 1'. The peripheries of the
heads of the syringes 1 and 1' were cooled by chillers to cool the
carbon dioxide to 10.degree. C., so that the carbon dioxide in a
liquid state was sucked into the syringe pumps 1 and 1'. The
high-pressure carbon dioxide having a low temperature to be in a
liquid state, rather than that having a high temperature to be in a
gaseous state, was stabilized in density and thus could be
precisely measured. The supply of the high-pressure carbon dioxide
to the respective syringe pumps 1 and 1' was done for every molding
shot.
[0090] The syringe pumps 1 and 1' measured after having the
high-pressure carbon dioxide sucked thereinto received a trigger
signal which was generated while the injection-molding section 100A
was plasticizing and measuring the resin. When a certain time
predetermined by a delay timer had passed since the output of this
trigger signal, the two syringe pumps 1 and 1' drived their pistons
for a given time according to constant flow rate controls
independently of each other.
[0091] By doing so, the high-pressure carbon dioxide fed from the
syringe pump 1 dissolved the materials charged in an oversaturation
state in the dissolution tank 12. The materials were dissolved at a
saturation solubility in the high-pressure carbon dioxide. Then,
the syringe pump 1 was driven to cause the high-pressure carbon
dioxide and the materials dissolved therein in a saturated state to
pass through the filter 22 and then supply them to the
injection-molding section 10A.
[0092] Then, the high-pressure carbon dioxide having these
materials dissolved and saturated therein and a high-pressure
carbon dioxide fed from the syringe pump 1' were allowed to pass
through the check valves 13 and 13', and then were mixed with each
other. Thus, a high-pressure fluid was formed. Since the
high-pressure carbon dioxide fed from the syringe pump 1' contained
no material, the materials were diluted with this high-pressure
fluid and thus were dissolved at non-saturation solubility in the
high-pressure carbon dioxide. The high-pressure fluid was supplied
to the molten resin in the plasticizing cylinder 105, through the
gas-introducing mechanism 107. During the supply of the
high-pressure fluid, the air operation valves 10 and 10' on the
suction side were closed, while the air operation valves 11 and 11
on the supply side were opened.
[0093] By diluting the materials dissolved in the high-pressure
carbon dioxide, the following two problems can be solved. The first
problem is that, when the materials are dissolved at saturation
solubility in the high-pressure carbon dioxide, the pressure of the
carbon dioxide lowers or the temperature thereof changes during the
supply thereof; the saturation solubility of the material tends to
decrease due to the influence of such a change, so that the
material oversaturates to precipitate. For example, when a loss in
pressure occurs during the supply of the material to the
plasticizing cylinder 105, the material precipitates at such a
supply site. As a result, the precipitated material clogs the pipe,
and the supply of the material having stable solubility becomes
difficult. However, the precipitation of the material during the
supply thereof can be prevented by supplying the material dissolved
in a non-saturation state.
[0094] The second problem is that, when an expensive material such
as a metal complex dissolved in a saturated state in a
high-pressure carbon dioxide is supplied, the supply amount of the
metal complex or the like is needed to be controlled by the supply
amount of carbon dioxide to a resin, with the result that the metal
complex or the like in an amount exceeding the amount required for
the surface modification of a molded article is supplied to the
molten resin, which leads to a higher cost. In other words, an
optimal supply amount of the high-pressure carbon dioxide to the
resin is determined substantially depending on the volume of a
desired molded article and molding conditions. Too small a supply
amount of the high-pressure carbon dioxide leads to insufficient
dispersion of the material in the resin. On the other hand, too
large a supply amount of the high-pressure carbon dioxide makes it
hard to infiltrate the material in the resin, so that the material
is apt to separate, with the result that the resultant molded
article tends to deform or foam. However, both of the supply
amounts of the high-pressure carbon dioxide and the material can be
controlled independently of each other to be optimized, by diluting
the material with a high-pressure carbon dioxide containing no
material.
[0095] In this Example, the high-pressure carbon dioxides from two
systems on the sides of the syringe pumps 1 and 1' may be merged
and mixed to form a high-pressure fluid, which may be mechanically
stirred with a magnetic stirrer 20 or the like or may be stirred by
using a pipe having a stirring function. The pressure of the
high-pressure fluid to be supplied to the resin (i.e., the pressure
of the high-pressure fluid which is being controlled in flow
amount) is controlled to be constant by the back pressure valve
14.
[0096] In the present invention, the temperature and pressure of
the high-pressure carbon dioxide may be optionally selected. In
this Example, the pressure thereof was set at 10 MPa, and the
temperature thereof, at a room temperature. While the pressures of
the high-pressure carbon dioxides in the interval from the pumps 1
and 1' to the high-pressure carbon dioxide-introducing mechanism
107 (including the dissolution tank 12 and the back pressure valve
14) were constantly maintained at 10 MPa, the syringe pumps 1 and
1' were ready to receive a trigger signal from the
injection-molding section 100A. Thus, the high-pressure carbon
dioxide-generating section 100B could supply predetermined amounts
of the high-pressure carbon dioxide and the material, at every time
when receiving the trigger signal which was generated while the
injection-molding section 100A was plasticizing and measuring the
resin.
Injection-Molding Method
[0097] With reference to FIGS. 3 and 4, the molding method employed
in this Example will be described. Firstly, the screw 120 in the
heating cylinder 105 was rotated. The pellets 54 of the resin
supplied to the heating cylinder 105 were molten and plasticized,
and the resulting molten resin is extruded to the portion 105B in
the front of the screw 120. The screw 120 was moved backward by the
extrusion of the molten resin, and was stopped at a predetermined
backward position. Thus, the amount of the molten resin
corresponding to the backward movement of the screw 120 was
measured.
[0098] Then, the injection-molding section 100A generated a trigger
signal, and simultaneously, the screw 120 was moved backward. By
this operation, the molten resin measured was decompressed. In this
Example, through an inner pressure monitor 108 for the molton
resin, provided around the flow front portion 105A of the heating
cylinder 105, it was confirmed that the inner pressure of the resin
was reduced to 4 MPa or lower.
[0099] Next, the high-pressure fluid was introduced into the molten
resin in the flow front portion 105A of the heating cylinder 105,
through the gas-introducing mechanism 107. By this operation, the
supercritical carbon dioxide having the fluorocompound and the
metal complex dissolved therein was introduced into the molten
resin.
[0100] In this Example, the ratio of the flow amount of the syringe
pump 1 in which the metal complex and the fluorine-based solution
were dissolved, to the flow amount of the syringe pump 1' in which
no material was not dissolved was set at 1:9. Since the diluted
metal complex or the like was introduced into the resin, the metal
complex or the like could be continuously and stably introduced
into the molten resin without precipitating. The weight of the
surface skin portion of the molded article obtained in this Example
was about 20 g. Thus, the amount of the regulated high-pressure
carbon dioxide infiltrated was about 0.6 g which was 3% by weight
of the molded article. The specific gravity of the high-pressure
carbon dioxide under the pressure and temperature conditions of
this Example was about 0.8 g/cm.sup.3. The feeding amount of the
high-pressure fluid per one shot was set at 0.5 ml. In this case,
0.05 ml of the carbon dioxide having the metal complex and the
fluorine-based solution dissolved therein was supplied, and 0.45 ml
of carbon dioxide alone was supplied.
[0101] In the meantime, the present inventors measured the
solubility of the materials in a high-pressure carbon dioxide of 15
MPa at a room temperature by the extraction method or the visual
observation. As a result, the solubility of the metal complex was
30 g/L (equivalent to 0.3 g in a 10 ml dissolution tank 12), and
the solubility of the fluorine-based solution was 200 g/L
(equivalent to 2 g in the 10 ml dissolution tank 12)). On the other
hand, the metal complex was dissolved in the fluorine-based
solution, and it was found that 8 g of the fluorine-based solution
was needed to completely dissolve 0.5 g of the metal complex.
Therefore, 0.5 g of the metal complex was dissolved in 8 g of the
fluorine-based solution, and the resulting solution was charged in
the dissolution tank 12.
[0102] When the introduction of the high-pressure fluid was
completed, the screw 120 was moved forward by a hack pressure and
thus is returned to a packing-starting position. By this operation,
the carbon dioxide, the fluorocompound and the metal complex
introduced into the flow front portion 105A in the front of the
screw 120 were homogeneously diffused in the molten resin.
[0103] When the above-described measuring operation was completed,
the air piston 109 was driven to open the shut-off valve 110, and
the molten resin was injected into the cavity 45 of the mold 42
defined by the movable mold 43 and the stationary mold 44, from the
heating cylinder 105, to pack the cavity 45 with the molten
resin.
[0104] FIG. 4 shows the schematic diagrams illustrating the molten
resin-packing conditions within the mold 101 during the
injection-packing operation. FIG. 4(a) shows the schematic diagram
illustrating the molten resin packed at the beginning. In this
beginning stage, the molten resin 105A' was packed in the flow
front portion 105A, and the fluorocompound and the carbon dioxide
infiltrated in this molten resin were diffused in the cavity 106
while being decompressed. In this stage, the molten resin 105A' in
the flow front portion 105A was allowed to flow and spread
contacting the surface of the mold, because of the fountain effect
produced by the packing of the molten resin, so that the skin layer
403 of the molded article was formed.
[0105] The molten resin was further injected to fill a whole of the
cavity 106. When the filling by injection was completed, the skin
layer 403 impregnated with the fluorocompound was formed on the
surfaces of the plastic molded article (or the molded body), and a
core layer 404 having substantially no material infiltrated therein
was formed inside the molded article. In this way, the amount of
the fluorocompound to be used could be decreased by decreasing the
amount of the inner fluorocompound which did not contribute to a
surface function, inside the molded article.
[0106] In this regard, by increasing the dwell pressure of the
molten resin after the primary packing, foaming of the molded
article because of gasification of the carbon dioxide could be
suppressed. In the molding method of this Example, the
supercritical carbon dioxide, etc. were infiltrated in the resin
only at the flow front portion 105A of the plasticizing cylinder
105, and thus, the amount of carbon dioxide to the entire amount of
the packed resin was small, accordingly. Therefore, the surface
condition of the molded article was hard to degrade, even if a
counter pressure was not applied to the interior of the cavity 106
of the mold 101. In this Example, the shaping of the molded article
was carried out simultaneously with the infiltration of the
fluorocompound in the surface of the molded article, as described
above,
Post-step for Surface-Modifying Method
[0107] In this Example, the molded article having the metal complex
and the fluorine-based solution infiltrated therein was subjected
to an annealing treatment. Specifically, the molded article was
annealed at 150.degree. C. for one hour, using a known
heat-treating furnace. The metal complex infiltrated in the molded
article was reduced by this heat treatment to function as catalytic
nuclei for plating. Again, in this Example, the catalytic nuclei
for plating could be collected on the surface portion of the molded
article, because the metal complex and the fluorocompound as low
molecular weight compounds infiltrated in the molded article tended
to easily bleed out due to this heat treatment.
[0108] The palladium catalytic nuclei which participated in the
plating and which were present in the proximity of the surface of
the molded article were likely to cause concentration spots on the
interior of the molded article obtained by the same molding shot,
and thus, there was a danger to cause non-adhesion of the plated
film or lower the adhesion strength of the plated film at the
portions where the catalytic nuclei were present at low densities.
However, the above-described bleed-out treatment was found to
produce the following effects: that is, the palladium catalytic
nuclei collected even on the portions with low densities of the
catalytic nuclei during the molding operation, so that a
concentration of the catalytic nuclei, sufficient to cause a quick
plating reaction could be obtained, with the result that the
non-adhesion of the plated film could be eliminated, and also that
an adhesion strength equivalent to that of a portion where the
concentration of the catalytic nuclei was high could be
obtained.
Evaluation of External Appearance of Molded Article
[0109] Next, the distribution state of the Pb complex infiltrated
in the molded article obtained by this injection molding was
visually observed. Polyamide 6 (Nylon 6, Novamid GH10, manufactured
by Mitsubishi Engineering-Plastics Corporation) used as the resin
for molding was usually white in color. In contrast,
hexafluoroacetyl-aceLonatopalladium (II) as the metal complex
infiltrated in the resin is brownish-red in color. The molded
article practically obtained in this Example was entirely colored
brownish-red, and the color density thereof was confirmed to be
substantially uniform.
[0110] Accordingly, it was confirmed that, in the molded article
shaped by the above-described method, the metal complex was
entirely and uniformly infiltrated in the surface of the molded
article. As a result of the present inventors' intensive studies,
it was confirmed that the color density of the molded article
obtained in this Example was sufficient as the concentration of the
catalytic nuclei for plating, based on the correlation data among
the accumulated variable color densities, the plating reactivity
and the adhesion strength. The variations of the color densities
and the concentration distributions of a plurality of molded
articles obtained by continuous 50 shots of injection molding
operations were examined. As a result, it was confirmed that the
variations thereof among the molded articles obtained by the 50
shots were very small.
Method for Forming Plated Film
[0111] Next, nonelectrolytic plating was made on the plastic molded
article (or the molded body) obtained by the above-described
process, to thereby form a plated film on the surface of the molded
article. Specifically, a solution mixture of a supercritical carbon
dioxide and an nonelectrolytic plating solution was used for the
nonelectrolytic plating.
[0112] FIG. 5 shows the schematic diagram of the nonelectrolytic
plating apparatus for batch process of this Example, using the
supercritical carbon dioxide. The apparatus 1100 includes a liquid
carbon dioxide bomb 2, a syringe pump 1 and a high-pressure
container 1101 as main components.
[0113] The high-pressure container 1101 could be controlled to an
optional temperature of from 30 to 145.degree. C. with water which
passed through the temperature-regulating channel 1136 and which
was controlled in temperature by a temperature regulator (not
shown). A high-pressure gas was sealed in the high-pressure
container 1101 by closing the container body 1131 with the lid 1132
sealed with a polyimide seal 1133 including a known spring therein.
Desirably, the high-pressure container 1101 was made of a
non-corrodible material such as SUS316, SUS316L, inconel,
hastelloy, titanium or the like. In this Example, SUS316L was
used.
[0114] The molded article surface-modified as described above was
suspended from the lid 1132 of the high-pressure container 1101,
and the high-pressure container 1101 was filled with an electroless
nickel plating solution up to 70% of the inner volume of the
high-pressure container 1101, and the magnetic stirrer 1135 was set
in the high-pressure container 1101.
[0115] The type of the nonolectrolytic plating solution usable in
the present invention may be of any of nickel-phosphorus,
nickel-boron, palladium, copper, silver, cobalt, etc. In the
present Example, a nickel-boron type nonelectrolytic plating
solution was used. The infiltration of high-pressure carbon dioxide
into the plating solution lowered the pH of the plating solution.
Since a preferable plating solution permits plating of a molded
article in a neutral or alkalescent to acidic bath, a
nickel-phosphorus type plating solution is desirable because it can
be used within a range of pH 4 to 6. When the pH of the plating
solution lowers, the concentration of phosphorus increases, which
results in a lower deposition rate. Therefore, the pH of the
plating solution may be previously increased. In this regard, a
conventional nonelectrolytic or electrolytic plated film may be
laminated on the nonelectrolytic plated film which was formed on
the molded article by using a high-pressure carbon dioxide,
according to the present invention.
[0116] In the nonelectrolytic plating using a high-pressure carbon
dioxide, according to the present invention, a plating reaction may
be carried out in a nonelectrolytic plating solution which contains
alcohol. Alcohols are known to be well compatible with
supercritical carbon dioxide under a high pressure, even if they
are not stirred. According to the present inventors' studies,
addition of an alcohol to a plating solution which contains water
as a main component facilitates the stable mixing of the plating
solution with a high-pressure carbon dioxide. Therefore, the use of
a fluorocompound or the stirring of the mixture becomes
unnecessary. The plating solution is infiltrated in a polymer
together with a high-pressure carbon dioxide to thereby cause a
plating reaction inside the polymer. Therefore, the addition of an
alcohol is preferable, since the surface tension of the plating
solution lowers, as compared with that of a plating solution
containing water alone.
[0117] Generally, an nonelectrolytic plating solution is prepared
by diluting a stock solution containing metal ions, a reducing
agent, etc. with water in a ratio recommended by a manufacturer. In
the present invention, an alcohol may be added to water in an
optional ratio. While the volume ratio of an alcohol to water may
be optionally selected, the volume ratio of the alcohol to the
total of water and the alcohol is preferably from 10 to 80%. When
the proportion of the alcohol is small, it is difficult to obtain a
stable mixture solution. When the proportion of the alcohol is too
large, the resultant plating bath tends to be unstable, because an
organic solvent such as ethanol is insoluble in nickel sulfate for
use in, for example, a nickel-phosphorus plating solution. The kind
of an alcohol to be used in the present invention may be optionally
selected. In this Example, ethanol was used, while there may be
used any of methanol, ethanol, n-propanol, isopropanol, butanol,
heptanol, ethylene glycol, etc.
[0118] In this Example, as a stock solution which contained a metal
salt, i.e., nickel sulfate, a reducing agent and a complexing
agent, NICORON DK (150 ml) manufactured by OKUNO CHEMICAL
INDUSTRIES CO., LTD, was added to a plating solution (1 L); and
water (350 ml) and ethanol (500 ml) as an alcohol were added to the
resulting mixture to thereby prepare the plating solution. That is,
50% of the alcohol was contained in the plating solution. It was
found that nickel sulfate insoluble in an alcohol could not be used
since the addition of 80% or more of the alcohol induced
precipitation of a lot of nickel sulfate.
[0119] As described above, the molded article sample 1130 and the
nonelectrolytic plating solution were charged in the high-pressure
container 1101, and then, a high-pressure carbon dioxide was
introduced into the high-pressure container 1101 to carry out an
nonelectrolytic plating treatment. The high-pressure carbon dioxide
from the liquid carbon dioxide bomb 2 was sucked up by the
high-pressure syringe pump 1 through the filter 1124 and was raised
in pressure to 15 MPa within the pump. After that, the manual valve
1125 was opened to introduce the high-pressure carbon dioxide into
the high-pressure container 1101. By controlling the pressure to be
constant with the manual valve 1125 opened, the syringe pump 1 used
in this Example could absorb fluctuation in pressure even when the
inner temperature and the density of the high-pressure carbon
dioxide in the high-pressure container 1101 changed. Therefore, the
inner pressure of the high-pressure container 1101 could be stably
maintained.
[0120] In the present invention, a nonelectrolytic plated film was
grown on the surface of a polymer molded article as follows: the
polymer molded article in which fine metal particles were
segregated in the inner portion of the surface was brought into
contact with a nonelectrolytic plating solution containing a
high-pressure carbon dioxide, at so low a temperature as not to
cause a plating reaction; and then, the temperatures of the polymer
molded article and of the plating solution containing the
high-pressure carbon dioxide were raised to thereby grow a
nonelectrolytic plated film on the surface of the polymer molded
article. By this procedure of the reaction, the nonelectrolytic
plating solution containing the high-pressure carbon dioxide was
infiltrated in the inner portion of the polymer molded article
before the plating reaction occurred, so that the nonelectrolytic
plated film could be grown from the inner portion of the polymer
molded article.
[0121] Practically, the initial temperatures of the high-pressure
container 1101 and of the plating solution 1137 were set at
50.degree. C. lower than the reaction temperature for plating,
i.e., 70 to 85.degree. C., by temperature-regulated water which
flowed in the temperature-regulating channel 1136. Under such a
temperature environment, a high-pressure carbon dioxide to be put
in a supercritical state was introduced into the high-pressure
container 1101. After that, the magnetic stirrer 1135 was rotated
at a high speed. In this initial reaction state, the
nonelectrolytic plating solution simply infiltrated the polymer
molded article without any growth of a plated film. After that, the
temperature of the high-pressure container 1101 was increased to
85.degree. C. so that a plating reaction was caused from the inner
portion of the polymer molded article.
[0122] After the completion of the above-described nonelectrolytic
plating treatment, the magnetic stirrer 1135 was stopped to
separate the carbon dioxide from the plating solution. After that,
the manual valve 1125 was closed, and simultaneously, the manual
valve 1145 was opened to exhaust the carbon dioxide. The polymer
molded article was taken out of the high-pressure container 1101.
Metallic gross was observed on a whole of the surface of the
polymer molded article. Further, a known Cu electrolytic plated
film with a thickness of 50 .mu.m was formed on the surface of the
resultant molded article under a normal pressure.
[0123] Then a heat cycle test was conducted on the molded articles
with the plated films formed thereon, while the temperature being
switched between -40.degree. C. and 85.degree. C. As a result,
there was no molded article from which the plated film peeled off
or which swelled. The adhesion strength of the plated film on the
flat portion of the molded article was measured by a vertical
tensile test (JISH 8630). As a result, the adhesion strength was 19
to 21 N/cm (average 20 N/cm). Thus, it was confirmed that a target
value for this test, i.e., 10 N/cm, which was an index for a
conventional ABS/etching plating, was sufficiently achieved. The
plating method of the present invention was therefore confirmed to
be effective to reliably form a plated film with high adhesion.
Example 2
[0124] In Example 2, the surface of a molded article was modified
in the same manner as in Example 1, except that the molded article
was subjected to a vacuuming treatment instead of the annealing
treatment, as the post-step for the resin molded
article-manufacturing process. After that, a plated film was formed
on the resultant molded article.
Post-Step for Surface-Modifying Method
[0125] In this Example, the plastic molded article (or molded body)
having the metal complex and the fluorine-based solution
infiltrated therein was subjected to a vacuuming treatment after
the molding process. Specifically, the molded article having the
metal complex and the fluorine-based solution infiltrated therein
was placed in a vacuum desiccator, and a vacuum pump (or a rotary
pump) was used to draw the molded article at a normal temperature
under a pressure of 1.times.10.sup.-1 Pa for 5 hours.
[0126] By drawing a vacuum at about 100.degree. C. in this way, the
metal complex and the fluorocompound both of which had low
molecular weights and which were infiltrated in the molded body
were apt to bleed out because of this heat treatment. For this
advantage, the metal complex, etc. which functioned as catalytic
nuclei for plating could be collected on the surface portion of the
molded article.
[0127] The palladium catalytic nuclei which participated in plating
and which were present in the proximity of the surface of the
molded body were likely to cause concentration spots in the molded
body obtained by the same molding shot. A plated film was not
adhered on parts of the molded article where the concentrations of
the catalytic nuclei were lower; or the adhesion strength of the
plated film tended to be lower at such parts of the molded article.
However, the above-described bleed-out treatment facilitated the
bleeding of the palladium catalytic nuclei even at parts of the
molded article where the concentrations of the catalytic nuclei
were lower during the molding process; thus, the parts of the
molded article, having lower concentrations of the catalytic
nuclei, were eliminated. Consequently, the entire surface of the
molded article could have so high a concentration of the catalytic
nuclei as to be sufficient to allow a plating reaction to rapidly
proceed thereover; non-adhesion of the plated film could be
eliminated; and the parts of the molded article, having a lower
concentration of the catalytic nuclei, could obtain an adhesion
strength equal to that of the parts thereof having a high
concentration of the catalytic nuclei.
Evaluation of External Appearance of Molded Article
[0128] Next, the distributed condition of the Pd complex
infiltrated in the molded article obtained by this injection
molding was visually observed in the same manner as in Example 1.
The molded article obtained in this Example was entirely colored
brownish-red attributed to the metal complex, and this color was
confirmed to have a sufficient density as the concentration of the
metal complex. When molded articles were manufactured by continuous
50 shots of injection molding, it was confirmed that variation in
the densities of the colors of the molded articles obtained from
these shots was very small.
[0129] A nonelectrolytic plating treatment using a high-pressure
carbon dioxide and a known Cu electrolytic plating treatment were
conducted on the molded articles in the same manner as in Example
1. Also, a heat cycle test was conducted on the molded articles
while the temperature being switched between -40.degree. C. and
85.degree. C. As a result, there was no molded article from which
the plated film was peeled off or which swelled. The adhesion
strength of the plated film on the flat portion of the molded
article was measured by a vertical tensile test (JISH 8630). As a
result, it was 19 to 21 N/cm (average 20 N/cm). Thus, it was
confirmed that a target value for this test, i.e., 10 N/cm (an
index for a conventional ABS/etching plating) was sufficiently
achieved. The plating method of the present invention was therefore
confirmed to be effective to reliably form a plated film with high
adhesion.
Example 3
[0130] In Example 3, the surface of a molded article was modified
as follows. A plastic molded article (or molded body) was
manufactured by injection molding in the same manner as in Example
1, and simultaneously, a mixture solution of a metal complex and a
fluorocompound was infiltrated in the molded article, using a
high-pressure carbon dioxide. After that, the fluorocompound in the
molded article was bled out and collected in the proximity of the
surface of the molded article to thereby modify the surface of the
molded article. A plated film (i.e., a metal film) was formed on
the modified surface of the molded article in the same manner as in
Example 1. In this regard, in Example 3, the mixture solution was
prepared by dissolving the metal complex in the fluorine-based
solution; this mixture solution was compressed with the syringe
pump 1 to have a predetermined pressure; and this high-pressure
mixture solution was dissolved in a high-pressure carbon dioxide to
form a high-pressure fluid.
Molding Apparatus
[0131] The schematic structure of the flow front injection-molding
apparatus used in this Example is shown in FIG. 6. This molding
apparatus 100 comprises an injection-molding section 100A and a
high-pressure carbon dioxide-generating section 100B, as well as
the molding apparatus shown in FIG. 3 which was used in Example 1.
The structure of the injection-molding section 100A is the same as
that used in Example 1.
[0132] The basic structure of the high-pressure carbon
dioxide-generating section 100B is the same as that used in Example
1. However, the liquid carbon dioxide bomb 2 is directly connected
to the side of the syringe pump 1' alone, and no dissolution tank
12 is not provided on the side of the syringe pump 1, while the
dissolution tank 12 is provided in Example 1, and a
material-stocking container 25 is connected to the syringe pump 1
instead, differently from the high-pressure carbon
dioxide-generating section 100B shown in FIG. 3.
[0133] Perfluorotripentylamine having hexafluoroacetyl
acetonatopalladium (II) dissolved therein was charged in the
material-stocking container 25. A pipe connected to the syringe
pump 1 was connected to the material-stocking container 25. The
syringe pump 1 sucked the fluorine-based solution having the metal
complex dissolved therein and directly fed a given required amount
of the same solution. On the other hand, the syringe pump 1'
supplied a high-pressure carbon dioxide which did not contain any
of these materials.
[0134] The mixture solution of the metal complex with the
fluorine-based solution and the high-pressure carbon dioxide, fed
from two directions, were allowed to pass through the check valves
13 and 13', respectively, and were then merged and mixed with each
other. Thus, the metal complex and the fluorine-based solution were
dissolved in the high-pressure carbon dioxide to form a
high-pressure fluid. In this regard, by controlling this mixing
ratio for the high-pressure fluid, it was possible to saturate or
unsaturate the metal complex and the fluorine-based solution in
this high-pressure fluid. It was also possible to prepare the
high-pressure fluid in an optional diluting ratio. Then, by feeding
required amounts of the metal complex and the fluorine-based
solution, it was possible to reliably control the amounts of the
metal complex and the fluorine-based solution to be infiltrated in
the molded article during the injection-molding, independently of
the amount of the high-pressure carbon dioxide to be infiltrated in
the molded article. It was also possible to decrease the variation
in the infiltrated amounts among each of the shots.
Injection-Molding Method
[0135] The molding method in this Example was the same as that in
Example 1. In this Example, the flow amounts of the syringe pumps 1
and 1' were controlled so that the supply amounts of the metal
complex, the fluorine-based solution and the high-pressure carbon
dioxide could be equal to the material supply amounts in Example 1
(the diluting ratio of the materials to the high-pressure carbon
dioxide: 1/10). That is, the supply amount of the high-pressure
carbon dioxide per one shot was 0.5 ml as in Example 2. The
solubility of the fluorine-based solution in the high-pressure
carbon dioxide was 100 ml/L (the specific gravity of the
fluorine-based solution: 2); and 0.005 ml of the fluorine-based
solution was dissolved in 0.05 ml of the high-pressure carbon
dioxide so as to adjust the diluting ratio of the materials to the
high-pressure carbon dioxide to 1/10. Therefore, the supply amount
of the metal complex and the fluorine-based solution per one shot
was 5 .mu.l.
Post-Step for Surface-Modifying Method
[0136] In the post-step in this Example, the molded article was
subjected to an annealing treatment at 150.degree. C. for one hour
in a known heat-treating furnace, in the same manner as in Example
1.
Evaluation of External Appearance of Molded Article
[0137] Next, the distributed condition of the Pd complex
infiltrated in the molded article obtained by this injection
molding was visually observed in the same manner as in Example 1.
The molded article obtained in this Example was entirely and
uniformly colored brownish-red attributed to the metal complex, and
this color was confirmed to have a sufficient density as the
concentration of the metal complex. A plurality of molded articles
were manufactured by continuous 50 shots of injection molding, and
variation in the densities of the colors and the concentration
distributions of the molded articles was examined. As a result, the
variation thereof was confirmed to be very small among the molded
articles obtained by the respective shots.
Method for Forming Plated Film
[0138] A plated film was formed on the molded article in the same
manner as in Example 1. As a result, metallic gloss was observed on
the entire surface of the polymer molded article. Further, a known
Cu electrolytic plated film with a thickness of 50 .mu.m was formed
on the surface of the resultant molded article under a normal
pressure.
[0139] Then a heat cycle test was conducted on the molded articles
with the plated films formed thereon, while the temperature being
switched between -40.degree. C. and 85.degree. C. As a result,
there was no molded article from which the plated film peeled off
or which swelled. The adhesion strength of the plated film on the
flat portion of the molded article was measured by a vertical
tensile test (JISH 8630). As a result, it was 19 to 21 N/cm
(average 20 N/cm). Thus, it was confirmed that a target value for
this test, i.e., 10 N/cm, which was an index for a conventional
ABS/etching plating, was sufficiently achieved. The plating method
of the present invention was therefore confirmed to be effective to
reliably form a plated film with high adhesion.
Example 4
[0140] In Example 4, the surface of a molded article was modified
as follows. A plastic molded article (or molded body) was
manufactured by injection molding in the same manner as in Example
1, and simultaneously, a mixture solution of a metal complex and a
fluorocompound was infiltrated in the molded article, using a
high-pressure carbon dioxide. After that, the fluorocompound in the
molded article was bled out and collected in the proximity of the
surface of the molded article to thereby modify the surface of the
molded article. A plated film (i.e., a metal film) was formed on
the modified surface of the molded article in the same manner as in
Example 1. In this regard, in Example 4, the metal complex and the
fluorine-based solution were dissolved in separate high-pressure
carbon dioxides, respectively, and both of the resulting solutions
were mixed to form a high-pressure fluid.
Molding Apparatus
[0141] The schematic structure of the flow front injection-molding
apparatus used in this Example is shown in FIG. 7. This molding
apparatus 100 used in this Example comprises an injection-molding
section 100A and a high-pressure carbon dioxide-generating section
100B as well as the molding apparatus shown in FIG. 3. The
structure of the injection-molding section 100A is the same as that
used in Example 1. The basic structure of the high-pressure carbon
dioxide-generating section 100B is the same as that used in Example
1, while a dissolution tank 12' is provided on the side of the
syringe pump 1', differently from the structure shown in FIG.
3.
[0142] Hexafluoroacetylacetonatopalladium (II) was charged in the
dissolution tank 12, and perfluorotripentylamine was charged in the
dissolution tank 12'. In this Example, two different materials were
dissolved in two separate high-pressure carbon dioxides,
respectively. Therefore, by controlling the supply ratio of the
metal complex and the fluorine-based solution, the amount of the
high-pressure carbon dioxide and the amount of the metal complex in
the high-pressure fluid obtained after the mixing can be controlled
independently of each other, as well as the case where the
materials are diluted with a high-pressure carbon dioxide
containing no material.
Injection-Molding Method
[0143] The molding method in this Example was the same as that in
Example 1. In this Example, the ratio of the flow amount of the
high-pressure carbon dioxide having the metal complex dissolved
therein to the flow amount of the high-pressure carbon dioxide
having the fluorine-based solution dissolved therein was set at
1:9. The supply amount per one shot was 0.5 .mu.l, as well as
Example 1. Accordingly, 0.05 ml of the high-pressure carbon dioxide
having the metal complex dissolved therein was supplied, and 0.45
ml of the high-pressure carbon dioxide having the fluorine-based
solution dissolved therein was supplied, per one shot.
Post-Step for Surface-Modifying Method
[0144] In the post-step in this Example, the molded article was
subjected to an annealing treatment at 150.degree. C. for one hour
in a known heat-treating furnace, in the same manner as in Example
1.
Evaluation of External Appearance of Molded Article
[0145] Next, the distributed condition of the Pd complex
infiltrated in the molded article obtained by this injection
molding was visually observed in the same manner as in Example 1.
While the molded article obtained in this Example was almost
entirely colored brownish-red attributed to the metal complex,
slight concentration spots in color were confirmed, and thus, light
colored parts were observed in the molded article. However, the
plated film was not so thin in thickness as to cause non-adhesion
of the plated film or as to extremely decrease the adhesion
strength of the plated film. Further, a plurality of molded
articles obtained by continuous 50 shots of injection-molding were
evaluated in the variations of the densities of the colors and the
concentration distributions thereof. As a result, there were found
two molded articles which were light in coloring as a whole.
Method for Forming Plated Film
[0146] A plated film was formed on the molded article in the same
manner as in Example 1. As a result, some parts poor in gloss were
observed in the resultant plated film, however, the plated film was
formed over the entire surface of the molded article. Further, a
known Cu electrolytic plated film with a thickness of 50 .mu.m was
formed on the surface of the molded article under a normal
pressure.
[0147] Then, a heat cycle test was conducted on the molded articles
with the plated films formed thereon, while the temperature being
switched between -40.degree. C. and 85.degree. C. As a result,
there was no molded article from which the plated film peeled off
or which swelled. The adhesion strength of the plated film on the
flat portion of the molded article was measured by a vertical
tensile test (JISH 8630). As a result, it was 12 to 18 N/cm
(average 15 N/cm). Thus, it was confirmed that a target value for
this test, i.e., 10 N/cm, which was an index for a conventional
ABS/etching plating, was sufficiently achieved. The plating method
of the present invention was therefore confirmed to be effective to
reliably form a plated film with high adhesion.
Example 5
[0148] In Example 5, the surface of a molded article was modified
as follows. A plastic molded article (or molded body) was
manufactured by injection molding in the same manner as in Example
1, and simultaneously, a mixture solution of a metal complex and a
fluorocompound was infiltrated in the molded article, using a
high-pressure carbon dioxide. After that, the fluorocompound in the
molded article was bled out and collected in the proximity of the
surface of the molded article to thereby modify the surface of the
molded article. A plated film (i.e., a metal film) was formed on
the modified surface of the molded article in the same manner as in
Example 1. In this regard, in Example 5, only one syringe pump 1
was used so as not to supply a high-pressure carbon dioxide
containing no material. Thus, the materials, not diluted, were
supplied.
Molding Apparatus
[0149] In this Example, the flow front injection-molding apparatus
shown in FIG. 3 which was used in Example 1 was used as it was.
However, in this Example, there were not used the syringe pump 1',
the air-operate valves 4' and 5' and the check valve 22'. The only
one syringe pump 1 was used to supply the high-pressure carbon
dioxide having the materials dissolved therein to the
injection-molding section. Perfluorotripentylamine having
hexafluoroacetyl-acetonatopalladium (II) dissolved therein was
charged in the dissolution tank 6, as well as Example 1.
Injection-Molding Method
[0150] The molding method in this Example was the same as that in
Example 1. In this Example, the supply amount per one shot was 0.5
ml, as well as Example 1. That is, 0.5 ml of the high-pressure
carbon dioxide in which the metal complex and the fluorine-based
solution were dissolved at saturation solubility was supplied per
one shot.
Post-Step for Surface-Modifying Method
[0151] In the post-step in this Example, the molded article was
subjected to an annealing treatment at 150.degree. C. for one hour
in a known heat-treating furnace, in the same manner as in Example
1.
Evaluation of External Appearance of Molded Article
[0152] Next, the distributed condition of the Pd complex
infiltrated in the molded article obtained by this injection
molding was visually observed in the same manner as in Example 1.
While the molded article obtained in this Example was almost
entirely colored brownish-red attributed to the metal complex, as
well as Example 4, slight concentration spots in color were
confirmed, and thus, lightly colored parts were observed in the
molded article. However, the plated film was not so thin in
thickness as to cause non-adhesion thereof or as to extremely
decrease the adhesion strength thereof. Further, a plurality of
molded articles obtained by continuous 50 shots of
injection-molding were evaluated in variation of the densities of
the colors thereof and the concentration distributions thereof. As
a result, there were found two molded articles which were light in
coloring as a whole. It was considered that the supply amount of
the metal complex for use in every shot for injection molding was
started to decrease during the continuous shots of injection
molding.
Method for Forming Plated Film
[0153] A plated film was formed on the molded article in the same
manner as in Example 1. As a result, the plated film was formed
over the entire surface of the molded article, although some parts
poor in gloss were observed in the plated film. Further, a known Cu
electrolytic plated film with a thickness of 50 .mu.m was formed on
the surface of the molded article under a normal pressure.
[0154] Then, a heat cycle test was conducted on the molded article
with the plated film formed thereon, while the temperature being
switched between -40.degree. C. and 85.degree. C. As a result,
there was no molded article from which the plated film peeled off
or which swelled. The adhesion strength of the plated film on the
flat portion of the molded article was measured by a vertical
tensile test (JISH 8630). As a result, it was 14 to 21 N/cm
(average 17 N/cm). Thus, it was confirmed that a target value for
this test, i.e., 10 N/cm, which was an index for a conventional
ABS/etching plating, was sufficiently achieved. The plating method
of the present invention was therefore confirmed to be effective to
reliably form a plated film with high adhesion.
Comparative Example 1
[0155] In Comparative Example 1, a molded article was obtained in
the same manner as in Example 1, except that a high-pressure carbon
dioxide having the metal complex alone dissolved therein was
supplied to the resin, without using the fluorine-based solution.
In detail, as the molding apparatus, the flow front injection
molding apparatus shown in FIG. 3 which was used in Example 1 was
used as it was. However, hexafluoroacetylacetonatopalladium (II)
alone was charged in the dissolution tank 6.
Injection-Molding Method
[0156] The molding method in this Example was the same as that
employed in Example 1. In this Example, the supply amount per one
shot of injection molding was 0.5 ml as well as Example 1. The
ratio of the flow amount of a high-pressure carbon dioxide having
the metal complex dissolved therein, from the syringe pump 1, to
the flow amount of a high-pressure carbon dioxide having no
material dissolved therein, from the syringe pump 1' was set at
1:9. Thus, 0.05 ml of the carbon dioxide having the metal complex
dissolved therein was supplied, and 0.45 ml of the carbon dioxide
having no material dissolved therein was supplied, per one
shot.
Post-Step for Surface-Modifying Method
[0157] In the post-step in this Example, the molded article was
subjected to an annealing treatment at 150.degree. C. for one hour
in a known heat-treating furnace, in the same manner as in Example
1.
Evaluation of External Appearance of Molded Article
[0158] Next, the distributed state of the Pd complex infiltrated in
the molded article obtained by this injection molding was visually
observed in the same manner as in Example 1. The coloring of
brownish-red attributed to the metal complex was observed on the
substantially entire surface of the molded article, as well as
Example 1. However, slight color density spots on the molded
article were observed, and thus, parts light in coloring were
observed on the molded article. In addition, the brownish-red
attributed to the metal complex, on the parts of the molded article
where the coloring was light, was too light to be visually
observed. Accordingly, there was confirmed possible non-adhesion of
the plated film or possible extremely weak adhesion strength of the
plated film. Further, variations in the color densities and
concentration distributions of a plurality of molded articles
obtained by continuous 50 shots of injection molding were
evaluated. As a result, the coloring of these molded articles was
far lighter than that of the molded article of Example 5, and there
were found seven molded articles which were likely to cause
non-adhesion of plated films. It was considered that the supply
amount of the metal complex per every shot became insufficient
during the continuous shots of injection molding.
Method for Forming Plated Film
[0159] A plated film was formed on the molded article in the same
manner as in Example 1. As a result, some parts of the resultant
plated film were poor in gloss and growth, however, the plated film
was formed over the entire surface of the molded article. Further,
a known Cu electrolytic plated film with a thickness of 50 .mu.m
was formed on the surface of the molded article under a normal
pressure.
[0160] Then, a heat cycle test was conducted on the molded articles
with the plated films formed thereon, while the temperature being
switched between -40.degree. C. and 85.degree. C. As a result, 50%
of all the molded articles as samples subjected to the heat cycle
test were found to have blisters with diameters of about 1 mm. The
adhesion strength of the plated film on the flat portion of the
molded article was measured by a vertical tensile test (JISH 8630).
As a result, it was 10 to 15 N/cm (average 12 N/cm). Thus, it was
confirmed that, while this value was not smaller than a target
value for this test, i.e., 10 N/cm, which was an index for a
conventional ABS/etching plating, sufficient improvement of the
adhesion strength was not achieved. The plating method of this
Comparative Example was therefore confirmed to be insufficient to
reliably form a plated film with high adhesion.
Example 6
[0161] In Example 6, a plated film was formed after the surface of
a molded article was modified in the same manner as in Example 1;
except that, as the fluorine-based solution, there was used
perfluoro-2,5,8,11,14-pentamethyl-3,6,9,12,15-pentaoxaoctadecanoyl
fluoride of the molecular formula: C.sub.18F.sub.36O.sub.6
(molecular weight: 996.2; and boiling point: 235.degree. C.,
manufactured by Sinquest Laboratory). In this regard, the metal
complex, i.e., hexafluoroacetylacetonatopalladium (II) had high
solubility in
perfluoro-2,5,8,11,14-pentamethyl-3,6,9,12,15-pentaoxaoctadecanoyl
fluoride.
Evaluation of External Appearance of Molded Article
[0162] Next, the distributed state of the Pd complex infiltrated in
the molded article obtained by this injection molding was visually
observed in the same manner as in Example 1. The coloring
attributed to the metal complex was observed on the substantially
entire surface of the molded article obtained in this Example.
However, slight color density spots were observed on the molded
article, and thus, parts light in coloring were observed in the
molded article. However, non-adhesion of the plated film was not
observed in even the parts of the plated film, light in coloring,
and the plated film was not so thin as to be extremely weak in
adhesion strength. Further, variations in the color densities and
concentration distributions of a plurality of molded articles
obtained by continuous 50 shots of injection molding were
evaluated. As a result, there were found three molded articles
which were light in coloring as a whole. It was considered that the
supply amount of the metal complex per every shot was started to
decrease during the continuous shots of injection molding.
Method for Forming Plated Film
[0163] A plated film was formed on the molded article in the same
manner as in Example 1. As a result, the plated film was formed
over the entire surface of the molded article, although some parts
of the plated film were slightly poor in gloss. Further, a known Cu
electrolytic plated film with a thickness of 50 .mu.m was formed on
the surface of the molded article under a normal pressure.
[0164] Then, a heat cycle test was conducted on the molded articles
with the plated films formed thereon, while the temperature being
switched between -40.degree. C. and 85.degree. C. As a result,
there was no molded article from which the plated film peeled off
or which swelled. The adhesion strength of the plated film on the
flat portion of the molded article was measured by a vertical
tensile test (JISH 8630). As a result, it was 16 to 18 N/cm
(average 17 N/cm). Thus, it was confirmed that a target value for
this test, i.e., 10 N/cm, which was an index for a conventional
ABS/etching plating, was sufficiently achieved. The plating method
of the present invention was therefore confirmed to be effective to
reliably form a plated film with high adhesion.
Example 7
[0165] In Example 7, a plated film was formed in the same manner as
in Example 1, except that, as the fluorine-based solution, there
was used
perfluoro-2,5,8,11,14-pentamethyl-3,6,9,12,15-pentaoxaoctadecanoyl
fluoride of the molecular formula: C.sub.18F.sub.36O.sub.6
(molecular weight: 996.2; and boiling point: 235.degree. C.,
manufactured by Sinquest Laboratory), and that, as the metal
complex, there was used nickel (II)
hexafluoroacetylacetonatohydride. In this regard, nickel (II)
hexafluoroacetylacetonatohydride had high solubility in
perfluoro-2,5,8,11,14-pentamethyl-3,6,9,12,15-pentaoxaoctadecanoyl
fluoride.
Evaluation of External Appearance of Molded Article
[0166] Next, the distributed state of the Pd complex infiltrated in
the molded article obtained by this injection molding was visually
observed in the same manner as in Example 1. The coloring
attributed to the metal complex was observed on the substantially
entire surface of the molded article. However, slight color density
spots were observed on the molded article, and thus, parts light in
coloring were observed in the molded article. However, non-adhesion
of the plated film was not observed on even the parts of the plated
film, light in coloring, and the plated film was not so thin as to
be extremely weak in adhesion strength. Further, variations in the
color densities and concentration distributions of a plurality of
molded articles obtained by continuous 50 shots of injection
molding were evaluated. As a result, there were found three molded
articles which were light in coloring as a whole. It was considered
that the supply amount of the metal complex per every shot was
started to decrease during the continuous shots of injection
molding.
Method for Forming Plated Film
[0167] A plated film was formed on the molded article in the same
manner as in Example 1. As a result, the plated film was formed
over the entire surface of the molded article, although some parts
of the plated film were slightly poor in gloss. Further, a known Cu
electrolytic plated film with a thickness of 50 .mu.m was formed on
the surface of the molded article under a normal pressure.
[0168] Then, a heat cycle test was conducted on the molded articles
with the plated films formed thereon, while the temperature being
switched between -40.degree. C. and 85.degree. C. As a result,
there was no molded article from which the plated film peeled off
or which swelled. The adhesion strength of the plated film on the
flat portion of the molded article was measured by a vertical
tensile test (JISH 8630). As a result, it was 12 to 14 N/cm
(average 13 N/cm). Thus, it was confirmed that a target value for
this test, i.e., 10 N/cm, which was an index for a conventional
ABS/etching plating, was sufficiently achieved. The plating method
of the present invention was therefore confirmed to be effective to
reliably form a plated film with high adhesion.
TABLE-US-00001 TABLE 1 Fluorine-based Metal High-pressure CO.sub.3
supply section Surface- solution complex Syringe pump 1 Syringe
pump 1' modifying method Ex. 1 A C Metal complex + CO.sub.2 alone
Heat treatment fluorine solution + CO.sub.3 (Dissolution tank) Ex.
2 A C Metal complex + CO.sub.2 alone Vacuuming treatment fluorine
solution + CO.sub.2 (Dissolution tank) Ex. 3 A C Metal complex +
CO.sub.2 alone Hear treatment fluorine solution (Stock container)
Ex. 4 A C Fluorine solution + CO.sub.2 Metal complex + CO.sub.2
Heat treatment Ex. 5 A C Metal complex + X Heat treatment fluorine
solution + CO.sub.2 Ex. 6 B C Metal complex + CO.sub.2 alone Heat
treatment fluorine solution + CO.sub.2 (Dissolution tank) Ex. 7 B D
Metal complex + CO.sub.2 alone Heat treatment fluorine solution +
CO.sub.3 (Dissolution tank) C. Ex. 1 -- C Metal complex CO.sub.2
alone Heat treatment Molded article Plated molded article External
appearance Adhesion strength of plated film (N/cm) Molded article
Adhesion of Heat cycle Max. - Molded article in each shot plated
film test Average Max. Min. min. Ex. 1 .circleincircle.
.circleincircle. .circleincircle. .circleincircle. 20 21 19 2 Ex. 2
.circleincircle. .circleincircle. .circleincircle. .circleincircle.
20 21 19 2 Ex. 3 .circleincircle. .circleincircle. .circleincircle.
.circleincircle. 20 22 19 3 Ex. 4 .largecircle. .largecircle.
.largecircle. .circleincircle. 15 18 12 6 Ex. 5 .largecircle.
.largecircle. .largecircle. .circleincircle. 17 21 14 7 Ex. 6
.largecircle. .largecircle. .largecircle. .circleincircle. 17 18 16
2 Ex. 7 .largecircle. .largecircle. .largecircle. .circleincircle.
13 14 12 2 C. Ex. 1 .DELTA. .DELTA. .DELTA. .circleincircle. 12 15
10 5 Fluorine-based solution A: Perfluorotripentylamine B:
Perfluoro-2,5,8,11,14-pentamethyl-3,6,9,12,15-pentaoxa-
octadecanoyl fluoride Metal complex C:
Hexafluoroacetylacetonatopalladium (II) D: Nickel (II)
hexafluoroacetylacetonatohydride
[0169] The results of the tests conducted after the plating of the
molded articles of Examples 1 to 7 and Comparative Example 1 are
summarized in Table 1. As shown in Table 1, all the plated films of
not only all Examples but also Comparative Example 1 were found to
achieve the target adhesion strength. However, the adhesion
strength of the plated film of Comparative Example 1 showed large
variation, and the average adhesion strength thereof was slightly
larger than the target value, i.e., 10 N/cm. In case where molded
articles with plated films of this type are commercially
manufactured, it can not be expected that the molded articles with
the target adhesion strength to plated films can be reliably
obtained by a continuous production process. On the other hand, in
Examples 1 to 3, the variation in the adhesion strengths of the
plated films was extremely small, and the averages of the adhesion
strengths thereof were sufficiently larger than the target value,
i.e., 10 N/cm. In case where molded articles with plated films of
any of theses types are commercially manufactured, molded articles
with the target adhesion strengths to plated films can be reliably
obtained by a continuous production process.
[0170] The following are considered as factors to obtain the
particularly superior results in Examples 1 to 3. Firstly, by
dissolving the Pd complex in the fluorine-based solution, the same
fluorine-based solution functions as a protective agent for the
metal complex exposed to a high temperature atmosphere during the
injection-molding. As a result, it is considered that the metal
complex dissolved in a high-pressure carbon dioxide could be
homogeneously dispersed in the resin. Secondly, a high-pressure
carbon dioxide having the Pd complex and the fluorine-based
solution dissolved and saturated therein is further diluted with
another high-pressure carbon dioxide, and therefore, these
materials unsaturated therein are supplied and introduced into the
resin. Therefore, the metal complex does not abnormally
precipitate, even when a pressure loss or a change in temperature
occurs in these materials introduced into the plasticizing cylinder
105 (or during the injection molding). As a result, the metal
complex dissolved in the high-pressure carbon dioxide can be
homogeneously dispersed in the resin. Thirdly, the fluorine-based
solution with a low molecular weight, apt to bleed out, is present
compatibilizing with the metal complex, and therefore, the metal
complex also easily bleeds out together with the fluorine-based
solution. Consequently, the Pd catalytic nuclei bleed out from the
inner portion of the molded article, up to parts thereof where the
densities of the Pd catalytic nuclei are low just after the
molding. As a result, it is considered that a density of the Pd
catalytic nuclei sufficient for a plating reaction can be easily
obtained.
INDUSTRIAL APPLICABILITY
[0171] According to the manufacturing process for the resin molded
article of the present invention, there is used a fluorine-based
solution capable of dissolving a fluorine-containing metal-complex,
together with a high-pressure carbon dioxide. Therefore, it becomes
possible to select a suitable fluorine-containing metal complex
from a wider range of metal complexes, as compared with the
conventional process, and it also becomes possible to modify the
surfaces of various kinds of molded articles by using this
fluorine-containing metal complex. In addition, there is used the
fluorine-based solution which is dissolved in the high-pressure
carbon dioxide together with the fluorine-containing metal complex
before a molding operation, and therefore, the fluorine-based
solution is not left to remain after the molding operation.
Consequently, any step for removing the fluorine-based solution
after the molding operation is not needed, so that a molded article
whose surface is not roughened can be obtained. According to the
method for forming a metal film in the present invention, a metal
film is formed over this surface-modified molded article, and
therefore, it is not needed to use a harmful etchant, as is the
case with the conventional plating method, and a metal film
superior in smoothness and adhesion strength can be formed.
[0172] For these advantages, the present invention can be suitably
applied to the formation of metal films on lamp reflectors, etc.
which require high reflectance, and the shaping of high frequency
molded interconnect devices (or MID) which require good electric
characteristics, millimeter-wave antennas, printed boards, etc. The
present invention also can be applied to a variety of industrial
fields and is also suitable as a method for forming a metal film at
a lower cost under a clean environment. It is further possible to
employ the metal film-forming method of the present invention for a
molded article with large dimensions and a complicated shape.
* * * * *